SkyWest (SKYW) 10-K 27 Feb 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Feb. 17, 2017	Jun. 30, 2016
Document and Entity Information
Entity Registrant Name	SKYWEST INC
Entity Central Index Key	793,733
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 1,362,182,737
Entity Common Stock, Shares Outstanding		51,845,731
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
CURRENT ASSETS:
Cash and cash equivalents	$ 146,766	$ 203,035
Marketable securities	409,898	286,668
Restricted cash	8,243	8,216
Income tax receivable	6,989	2,871
Receivables, net	46,916	62,162
Inventories, net	118,509	140,312
Prepaid aircraft rents	162,360	195,216
Deferred tax assets	129,285	100,730
Other current assets	18,111	18,360
Total current assets	1,047,077	1,017,570
PROPERTY AND EQUIPMENT:
Aircraft and rotable spares	4,839,501	5,242,790
Deposits on aircraft	38,800	38,150
Buildings and ground equipment	261,704	275,788
Total property and equipment, gross	5,140,005	5,556,728
Less-accumulated depreciation and amortization	(1,318,308)	(2,085,981)
Total property and equipment, net	3,821,697	3,470,747
OTHER ASSETS
Intangible assets, net	8,249	10,499
Long-term prepaid assets	218,505	229,180
Other assets	41,723	53,988
Total other assets	268,477	293,667
Total assets	5,137,251	4,781,984
CURRENT LIABILITIES:
Current maturities of long-term debt	305,460	268,667
Accounts payable	241,215	279,864
Accrued salaries, wages and benefits	139,885	138,291
Taxes other than income taxes	15,618	17,176
Other current liabilities	45,087	44,028
Total current liabilities	747,265	748,026
OTHER LONG TERM LIABILITIES	50,844	56,191
LONG TERM DEBT, net of current maturities	2,240,051	1,659,234
DEFERRED INCOME TAXES PAYABLE	694,689	749,575
DEFERRED AIRCRAFT CREDITS	53,459	62,523
COMMITMENTS AND CONTINGENCIES (Note 5)
STOCKHOLDERS' EQUITY:
Preferred stock, 5,000,000 shares authorized; none issued
Common stock, no par value, 120,000,000 shares authorized; 79,781,305 and 79,020,371 shares issued, respectively	657,353	641,643
Retained earnings	1,103,751	1,275,142
Treasury stock, at cost, 28,015,386 and 28,015,386 shares, respectively	(410,090)	(410,090)
Accumulated other comprehensive loss	(71)	(260)
Total stockholders' equity	1,350,943	1,506,435
Total liabilities and stockholders' equity	$ 5,137,251	$ 4,781,984

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2016	Dec. 31, 2015
CONSOLIDATED BALANCE SHEETS
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Common stock, par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares issued	79,781,305	79,020,371
Treasury stock, at cost, shares	28,015,386	28,015,386

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
OPERATING REVENUES:
Passenger	$ 3,051,414	$ 3,030,023	$ 3,168,000
Ground handling and other	69,792	65,540	69,447
Total operating revenues	3,121,206	3,095,563	3,237,447
OPERATING EXPENSES:
Salaries, wages and benefits	1,211,380	1,203,312	1,258,155
Aircraft maintenance, materials and repairs	569,306	604,863	682,773
Depreciation and amortization	284,969	264,507	259,642
Aircraft rentals	262,602	273,696	305,334
Aircraft fuel	122,284	118,124	193,247
Ground handling services	72,659	82,694	123,917
Station rentals and landing fees	49,482	54,167	51,024
Special items	465,649		74,777
Other operating expenses	255,559	259,685	263,730
Total operating expenses	3,293,890	2,861,048	3,212,599
OPERATING INCOME (LOSS)	(172,684)	234,515	24,848
OTHER INCOME (EXPENSE):
Interest income	2,143	1,997	4,096
Interest expense	(78,177)	(75,850)	(65,995)
Other, net	(94)	33,660	20,708
Total other expense, net	(76,128)	(40,193)	(41,191)
INCOME (LOSS) BEFORE INCOME TAXES	(248,812)	194,322	(16,343)
PROVISION (BENEFIT) FOR INCOME TAXES	(87,226)	76,505	7,811
NET INCOME (LOSS)	$ (161,586)	$ 117,817	$ (24,154)
BASIC EARNINGS (LOSS) PER SHARE (in dollars per share)	$ (3.14)	$ 2.31	$ (0.47)
DILUTED EARNINGS (LOSS) PER SHARE (in dollars per share)	$ (3.14)	$ 2.27	$ (0.47)
Weighted average common shares:
Basic (in shares)	51,505	51,077	51,237
Diluted (in shares)	51,505	51,825	51,237
COMPREHENSIVE INCOME (LOSS):
Net income (loss)	$ (161,586)	$ 117,817	$ (24,154)
Proportionate share of equity method investee foreign currency translation adjustment, net of taxes			(1,129)
Net unrealized appreciation (depreciation) on marketable securities, net of taxes	189	29	(719)
TOTAL COMPREHENSIVE INCOME (LOSS)	$ (161,397)	$ 117,846	$ (26,002)

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Total
Balance at Dec. 31, 2013	$ 618,511	$ 1,197,819	$ (382,950)	$ 1,559	$ 1,434,939
Balance (in shares) at Dec. 31, 2013	77,326		(26,096)
Increase (Decrease) in Stockholders' Equity
Net income (loss)		(24,154)			(24,154)
Proportionate share of other companies foreign currency translation adjustment, net of tax of $XXX and $678 for 2015 and 2014, respectively				(1,129)	(1,129)
Net unrealized depreciation on marketable securities net of tax of $98, $18 and $437 for 2016, 2015 and 2014, respectively				(719)	(719)
Exercise of common stock options and vested restricted stock units	$ 287				287
Exercise of common stock options and vested restricted stock units (in shares)	330
Sale of common stock under employee stock purchase plan	$ 3,752				3,752
Sale of common stock under employee stock purchase plan (in shares)	295
Stock based compensation expense related to the issuance of stock options and restricted stock units	$ 5,318				5,318
Tax deficiency from exercise of common stock options	(1,347)				(1,347)
Treasury stock purchases			$ (8,414)		(8,414)
Treasury stock purchases (in shares)			(669)
Cash dividends declared ( $0.16 per share)		(8,187)			(8,187)
Balance at Dec. 31, 2014	$ 626,521	1,165,478	$ (391,364)	(289)	1,400,346
Balance (in shares) at Dec. 31, 2014	77,951		(26,765)
Increase (Decrease) in Stockholders' Equity
Net income (loss)		117,817			117,817
Net unrealized depreciation on marketable securities net of tax of $98, $18 and $437 for 2016, 2015 and 2014, respectively				29	29
Exercise of common stock options and vested restricted stock units	$ 8,490				8,490
Exercise of common stock options and vested restricted stock units (in shares)	815
Sale of common stock under employee stock purchase plan	$ 3,430				3,430
Sale of common stock under employee stock purchase plan (in shares)	254
Stock based compensation expense related to the issuance of stock options and restricted stock units	$ 5,368				5,368
Tax deficiency from exercise of common stock options	(2,166)				(2,166)
Treasury stock purchases			$ (18,726)		(18,726)
Treasury stock purchases (in shares)			(1,250)
Cash dividends declared ( $0.16 per share)		(8,153)			(8,153)
Balance at Dec. 31, 2015	$ 641,643	1,275,142	$ (410,090)	(260)	1,506,435
Balance (in shares) at Dec. 31, 2015	79,020		(28,015)
Increase (Decrease) in Stockholders' Equity
Net income (loss)		(161,586)			(161,586)
Net unrealized depreciation on marketable securities net of tax of $98, $18 and $437 for 2016, 2015 and 2014, respectively				189	189
Exercise of common stock options and vested restricted stock units	$ 4,979				4,979
Exercise of common stock options and vested restricted stock units (in shares)	609
Sale of common stock under employee stock purchase plan	$ 3,163				3,163
Sale of common stock under employee stock purchase plan (in shares)	152
Stock based compensation expense related to the issuance of stock options and restricted stock units	$ 7,568				7,568
Cash dividends declared ( $0.16 per share)		(9,805)			(9,805)
Balance at Dec. 31, 2016	$ 657,353	$ 1,103,751	$ (410,090)	$ (71)	$ 1,350,943
Balance (in shares) at Dec. 31, 2016	79,781		(28,015)

CONSOLIDATED STATEMENTS OF STO6

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY
Proportionate share of other companies foreign currency translation adjustment, tax			$ 678
Net unrealized appreciation (depreciation) on marketable securities, tax	$ (98)	$ (18)	$ 437
Cash dividends declared (in dollars per share)	$ 0.19	$ 0.16	$ 0.16

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ (161,586)	$ 117,817	$ (24,154)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	284,969	264,507	259,642
Stock based compensation expense	7,568	5,368	5,318
Loss on sale of property and equipment			4,016
Gain from equity ownership in TRIP Airlines			(24,922)
Gain from early extinguishment of debt	(1,279)	(33,660)
Capitalized Brasilia EMB-120 engine overhauls			(18,812)
Special items	465,649		74,777
Net increase (decrease) in deferred income taxes	(83,441)	73,844	5,054
Changes in operating assets and liabilities:
Decrease (increase) in restricted cash	(27)	3,366	637
Decrease in receivables	15,260	21,076	25,540
Increase in income tax receivable	(4,118)	(92)	(1,939)
Increase in inventories	(1,986)	(2,860)	(890)
Decrease (increase) in other current assets and prepaid aircraft rents	37,569	(28,598)	(25,985)
Decrease in deferred aircraft credits	(8,108)	(8,635)	(7,672)
Increase (decrease) in accounts payable and accrued aircraft rents	(47,563)	9,690	5,852
Increase (decrease) in other current liabilities	3,758	(4,498)	13,668
NET CASH PROVIDED BY OPERATING ACTIVITIES	506,665	417,325	290,130
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of marketable securities	(2,511,388)	(1,170,439)	(326,964)
Sales of marketable securities	2,388,168	1,299,069	398,148
Proceeds from the sale of aircraft, property and equipment	3,008	10,308	9,473
Proceeds from installment payment from sale of equity shares in TRIP Airlines			17,237
Proceeds from settlement of residual value guarantee aircraft agreements	90,000
Acquisition of property and equipment:
Aircraft and rotable spare parts	(1,138,963)	(710,871)	(653,473)
Deposits on aircraft	(650)
Buildings and ground equipment	(14,350)	(10,405)	(21,966)
Return of deposits on aircraft		1,850
Decrease (increase) in other assets	7,097	10,772	(7,681)
NET CASH USED IN INVESTING ACTIVITIES	(1,177,078)	(569,716)	(585,226)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of long-term debt	926,069	591,881	460,600
Principal payments on long-term debt	(302,158)	(354,277)	(185,357)
Net proceeds from issuance of common stock	8,142	9,754	2,692
Purchase of treasury stock		(18,726)	(8,414)
Decrease (increase) in debt issuance cost	(8,653)	2,779	(4,591)
Payment of cash dividends	(9,256)	(8,260)	(8,195)
NET CASH PROVIDED BY FINANCING ACTIVITIES	614,144	223,151	256,735
Increase (Decrease) in cash and cash equivalents	(56,269)	70,760	(38,361)
Cash and cash equivalents at beginning of period	203,035	132,275	170,636
CASH AND CASH EQUIVALENTS AT END OF PERIOD	146,766	203,035	132,275
Non-cash investing activities:
Acquisition of rotable spare parts	5,688
Cash paid during the period for:
Interest, net of capitalized amounts	76,589	80,657	67,763
Income taxes	$ 1,212	$ 5,104	$ 2,066

Nature of Operations and Summar

Nature of Operations and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
Nature of Operations and Summary of Significant Accounting Policies
Nature of Operations and Summary of Significant Accounting Policies	(1) Nature of Operations and Summary of Significant Accounting Policies SkyWest, Inc. (the “Company”), through its subsidiaries, SkyWest Airlines, Inc. (“SkyWest Airlines”) and ExpressJet Airlines, Inc. (“ExpressJet”), operates the largest regional airlines in the United States. As of December 31, 2016, SkyWest Airlines and ExpressJet offered scheduled passenger service under code-share agreements with United, Delta, American and Alaska with approximately 3,160 total daily departures to different destinations in the United States, Canada, Mexico and the Caribbean. Additionally, the Company provides airport customer service and ground handling services for other airlines throughout its system. As of December 31, 2016, the Company had 652 aircraft in scheduled service out of a combined fleet of 685 aircraft consisting of the following: CRJ200 CRJ700 CRJ900 ERJ135 ERJ145 E175 EMB120 Total United — — Delta — — — American — — — — Alaska — — — — — — Aircraft in scheduled service — Subleased to an un-affiliated entity — — — — — — Other* — — — Total Fleet *Other aircraft consisted of leased aircraft removed from service that were in the process of being returned to the lessor and owned aircraft removed from service that are in the process of being sold. For the year ended December 31, 2016, approximately 52.2% of the Company’s aggregate capacity was operated for United, approximately 36.5% was operated for Delta, approximately 6.3% was operated for American, and approximately 5.0% was operated for Alaska. SkyWest Airlines has been a code-share partner with Delta since 1987, United since 1997, Alaska since 2011 and American since 2012. As of December 31, 2016, SkyWest Airlines operated as a Delta Connection carrier primarily in Salt Lake City and Minneapolis, a United Express carrier primarily in Los Angeles, San Francisco, Denver, Houston, Chicago and the Pacific Northwest, an American carrier primarily in Chicago, Los Angeles and Phoenix and an Alaska carrier primarily in the Pacific Northwest. As of December 31, 2016, ExpressJet operated as a Delta Connection carrier primarily in Atlanta and Detroit, a United Express carrier primarily in Chicago (O’Hare), Cleveland, Newark and Houston and an American carrier primarily in Dallas. Basis of Presentation The Company’s consolidated financial statements include the accounts of the Company and the SkyWest Airlines, ExpressJet and SkyWest Leasing segments, with all inter‑company transactions and balances having been eliminated. In preparing the accompanying consolidated financial statements, the Company has reviewed, as determined necessary by the Company’s management, events that have occurred after December 31, 2016, through the filing date of the Company’s annual report with the U.S. Securities and Exchange Commission. The Company reclassified certain prior period amounts to conform to the current period presentation. Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three months or less to be cash equivalents. The Company classified $8.2 million of cash as restricted cash collateralizing letters of credit under the Company’s workers’ compensation insurance policy and classified it accordingly in the consolidated balance sheets as of December 31, 2016 and 2015. Marketable Securities The Company’s investments in marketable debt and equity securities are deemed by management to be available-for-sale and are reported at fair market value with the net unrealized appreciation (depreciation) reported as a component of accumulated other comprehensive income (loss) in stockholders’ equity. At the time of sale, any realized appreciation or depreciation, calculated by the specific identification method, is recognized in other income and expense. The Company’s position in marketable securities as of December 31, 2016 and 2015 was as follows (in thousands): Gross unrealized Gross unrealized At December 31, 2016 Amortized Cost holding gains holding losses Fair market value Total cash and cash equivalents $ $ — $ — $ Available-for-sale securities: Bond and bond funds $ $ — $ $ Asset backed securities — — Total available-for-sale securities $ $ — $ $ Total cash and cash equivalents and available for sale securities $ $ — $ $ Gross unrealized Gross unrealized At December 31, 2015 Amortized Cost holding gains holding losses Fair market value Total cash and cash equivalents $ $ — $ — $ Available-for-sale securities: Bond and bond funds $ $ — $ $ Asset backed securities — Total available-for-sale securities $ $ $ $ Total cash and cash equivalents and available for sale securities $ $ $ $ Marketable securities had the following maturities as of December 31, 2016 (in thousands): Maturities Amount Year 2017 $ Thereafter As of December 31, 2016 and 2015, the Company had classified $409.9 million and $286.7 million of marketable securities, respectively, as short‑term since it had the intent to maintain a liquid portfolio and the ability to redeem the securities within one year. The Company has classified $2.3 million of investments as non‑current and has identified them as “Other assets” in the Company’s consolidated balance sheet as of December 31, 2015 (see Note 6). Inventories Inventories include expendable parts, fuel and supplies and are valued at cost (FIFO basis) less an allowance for obsolescence based on historical results, excess parts and management’s expectations of future operations. Expendable inventory parts are charged to expense as used. An obsolescence allowance for flight equipment expendable parts is accrued based on estimated lives of the corresponding fleet types and salvage values. The inventory allowance as of December 31, 2016 and 2015 was $40.5 million and $13.9 million, respectively. The significant increase in 2016 was related to additional excess inventory identified as part of the impairment analysis of the 50-seat aircraft. See Note 8, Special items, for additional detail on the impairment. These allowances are based on management estimates, which can be modified based on future changes in circumstances. Property and Equipment Property and equipment are stated at cost and depreciated over their useful lives to their estimated residual values using the straight‑line method as follows: Assets Depreciable Life Residual Value New Aircraft 18 years % Used Aircraft, rotable spares, and spare engines up to 18 years 0 - 30 % Ground equipment up to 10 years % Office equipment up to 7 years % Leasehold improvements Shorter of 15 years or lease term % Buildings 20 – 39.5 years % Impairment of Long-Lived Assets As of December 31, 2016, the Company had approximately $3.8 billion of property and equipment and related assets. Additionally, as of December 31, 2016, the Company had approximately $8.2 million in intangible assets. In accounting for these long‑lived and intangible assets, the Company makes estimates about the expected useful lives of the assets, the expected residual values of certain of these assets, and the potential for impairment based on the fair value of the assets and the cash flows they generate. On September 7, 2005, the Company acquired all of the issued and outstanding capital stock of Atlantic Southeast and recorded an intangible asset for specifically identifiable contracts of approximately $33.7 million relating to the acquisition. The intangible asset is being amortized over fifteen years under the straight‑line method. As of December 31, 2016 and 2015, the Company had $25.5 million and $23.3 million in accumulated amortization expense, attributable to the acquisition, respectively. Factors indicating potential impairment include, but are not limited to, significant decreases in the market value of the long‑lived assets, a significant change in the condition of the long‑lived assets and operating cash flow losses associated with the use of the long‑lived assets. On a periodic basis, the Company evaluates whether impairment indicators are present. When considering whether or not impairment of long‑lived assets exists, the Company groups similar assets together at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets and liabilities and compare the undiscounted cash flows for each asset group to the net carrying amount of the assets supporting the asset group. Asset groupings are done at the fleet or contract level. In December 2016, the Company decided to remove CRJ200 aircraft from ExpressJet’s operation. In connection therewith, the Company plans to remove approximately 46 CRJ200 aircraft from its fleet during 2017. Additionally, in December 2016, the Company entered into a termination agreement covering Bombardier’s residual value guarantee (“RVG”) agreements on 76 CRJ200 aircraft owned by SkyWest Airlines and ExpressJet whereby it agreed to terminate Bombardier’s future RVG commitment in exchange for a cash payment and other consideration valued at $125 million. The agreement also eliminated the Company`s future requirement to return the aircraft to a mid-time maintenance condition and certain remarketing activities. This termination agreement allowed for the acceleration of the retirement of the CRJ 200 fleet. As a result of the scheduled reduction in the CRJ200 fleet in 2017, the termination of the RVG agreements with Bombardier and the current market values of its CRJ200 aircraft excluding Bombardier’s RVGs, the Company concluded that indicators of impairment existed and therefore, evaluated its CRJ200 fleet and related assets for impairment. Pursuant to Accounting Standards Codification (“ASC”) 360-10, Impairment and Disposal of Long-Lived Assets, the Company determined that separate asset groups existed based on the various major partner contracts. A recoverability test was performed utilizing estimated undiscounted future cash flows for each asset group pursuant to applicable contracts with the major partners and associated expenses as well as the value the Company would realize upon disposal of aircraft. This was compared to the carrying value of the related assets resulting in a cash flow deficiency indicating that an impairment existed. The impairment analysis required the Company to perform an assessment of the fair value of its long-lived assets related to the CRJ200 aircraft within the asset groups utilized in the recoverability test. The Company engaged a third party to assist in determining the fair value of certain of the long-lived assets, including the aircraft, spare engines and fixed asset spare parts inventory. These values were estimated based on listed market values or recent third-party market transactions for similar assets. Additionally, the Company estimated the fair value of certain long-lived prepaid lease assets using the net present value of estimated current CRJ200 lease rates. All fair values are considered to be Level 3 within the fair value hierarchy. The amounts the Company may ultimately realize from the disposal of its CRJ200 long-lived assets may vary from the December 31, 2016 fair value assessments. See Note 8, Special Items , for the impairment charges recorded during the year ended December 31, 2016 related to the CRJ200 long-lived assets. Additionally, the Company’s fixed-fee contract with United covering Embraer ERJ145 regional jet aircraft ("ERJ145") is scheduled to expire at the end of 2017, subject to United’s two one-year extension rights intended to facilitate an orderly return of ERJ145 aircraft to United. The ERJ145 aircraft are leased from United and the Company is obligated to return the aircraft to United as each aircraft is scheduled to terminate under the contract. There are no significant unreimbursed return related costs associated with these lease returns. Under the terms of the fixed-fee contract, the Company anticipates removing approximately 45 ERJ145s from its fleet in 2017 and returning the aircraft to United. Due to the uncertainty regarding the probability of extending the ERJ145 fixed-fee arrangement with United beyond the existing terms and as the Company is obligated to return these aircraft to United upon the contract expiration, the Company also evaluated its ERJ145 related assets for impairment including spare engines and related spare parts inventory. The Company engaged a third party to assist in determining the fair value of the spare parts engines and inventory. The spare engines and inventory were valued based on recent market transactions for similar assets. All fair values are considered to be Level 3 within the fair value hierarchy. The amounts the Company may ultimately realize from the disposal of its ERJ145 long-lived assets may vary from the December 31, 2016 fair value assessments. See Note 8, Special Items , for the impairment charges recorded during the year ended December 31, 2016 related to the ERJ145 long-lived assets. The Company did not recognize any impairment charges of long-lived assets during 2015. In 2014, the Company had impairments on several long-lived assets relating to Embraer Brasilia EMB 120 (“EMB120”) turboprop aircraft, ERJ145 aircraft type specific assets and an aircraft paint facility located in Saltillo, Mexico. See Note 8, Special Items , for the impairment charges recorded during the year ended December 31, 2014 related to these long-lived assets. Capitalized Interest Interest is capitalized on aircraft purchase deposits as a portion of the cost of the asset and is depreciated over the estimated useful life of the asset. During the years ended December 31, 2016, 2015 and 2014, the Company capitalized interest costs of approximately $1.5 million, $2.2 million, and $1.8 million, respectively. Maintenance The Company operates under a U.S. Federal Aviation Administration approved continuous inspection and maintenance program. The Company uses the direct expense method of accounting for its regional jet engine overhauls wherein the expense is recorded when the overhaul event occurs. The Company has engine services agreements with third-party vendors to provide long-term engine services covering the scheduled and unscheduled repairs for certain of its Bombardier CRJ700 Regional Jets (“CRJ700s”), Embraer ERJ145 regional jet aircraft and Embraer E175 jet (“E175”) aircraft. Under the terms of the agreements, the Company pays a fixed dollar amount per engine hour flown on a monthly basis and the third-party vendors will assume the responsibility to repair the engines at no additional cost to the Company, subject to certain specified exclusions. Maintenance costs under these contracts are recognized when the engine hour is flown pursuant to the terms of each contract. The costs of maintenance for airframe and avionics components, landing gear and normal recurring maintenance are expensed as incurred. Passenger and Ground Handling Revenues The Company recognizes passenger and ground handling revenues when the service is provided under its code-share agreements. Under the Company’s fixed-fee arrangements (referred to as “fixed-fee arrangements, “fixed-fee contracts” or “capacity purchase agreements”) with Delta, United, American and Alaska (each, a “major airline partner”), the major airline partner generally pays the Company a fixed-fee for each departure, flight or block time incurred, and an amount per aircraft in service each month with additional incentives based on flight completion and on time performance. The major airline partner also directly reimburses the Company for certain direct expenses incurred under the fixed-fee arrangement such as fuel expense and landing fee expenses. Under the fixed-fee arrangements, revenue is earned when each flight is completed. Under the Company’s fixed-fee agreements with Delta, United, American and Alaska, the compensation structure generally consists of a combination of agreed‑upon rates for operating flights and direct reimbursement for other certain costs associated with operating the aircraft. A portion of the Company’s contract flying compensation is designed to reimburse the Company for certain aircraft ownership costs. The aircraft compensation structure varies by agreement, but is intended to cover either the Company’s aircraft principal and interest debt service costs, its aircraft depreciation and interest expense or its aircraft lease expense costs while the aircraft is under contract. Under the Company’s ExpressJet United Express ERJ Agreement and ExpressJet American ERJ145 Agreement, the major airline partner provides the aircraft to the Company for a nominal amount. The Company has concluded that a component of its revenue under these agreements is rental income, inasmuch as the agreements identify the “right of use” of a specific type and number of aircraft over a stated period of time. The amounts deemed to be rental income under the agreements for the years ended December 31, 2016, 2015 and 2014 were $516.0 million, $504.9 million and $497.0 million, respectively. These amounts are reflected as passenger revenues on the Company’s consolidated statements of comprehensive income (loss). The Company has not separately stated aircraft rental income and aircraft rental expense in the consolidated statement of comprehensive income (loss) since the use of the aircraft is not a separate activity of the total service provided. In the event that the contractual rates under the agreements have not been finalized at quarterly or annual financial statement dates, the Company records revenues based on the lower of prior period’s approved rates, as adjusted to reflect any contract negotiations and the Company’s estimate of rates that will be implemented in accordance with revenue recognition guidelines. In the event the Company has a reimbursement dispute with a major airline partner, the Company evaluates the dispute under its established revenue recognition criteria and, provided the revenue recognition criteria have been met, the Company recognizes revenue based on management’s estimate of the resolution of the dispute. In several of the Company’s agreements, the Company is eligible for incentive compensation upon the achievement of certain performance criteria. The incentives are defined in the agreements and are being measured and determined on a monthly, quarterly or semi-annual basis. At the end of each period, the Company calculates the incentives achieved during that period and recognizes revenue accordingly. The Company’s passenger and ground handling revenues could be impacted by a number of factors, including changes to the Company’s code‑share agreements with Delta, United, Alaska or American, contract modifications resulting from contract re‑negotiations, the Company’s ability to earn incentive payments contemplated under the Company’s code‑share agreements and settlement of reimbursement disputes with the Company’s major airline partners. Under a Revenue Sharing Arrangement (referred to as a “revenue-sharing” or “prorate” arrangement), the major airline and regional airline negotiate a passenger fare proration formula, pursuant to which the regional airline receives a percentage of the ticket revenues for those passengers traveling for one portion of their trip on the regional airline and the other portion of their trip on the major airline. Revenue is recognized under the Company’s prorate flying agreements when each flight is completed based upon the portion of the prorate passenger fare the Company anticipates that it will receive for each completed flight. Other ancillary revenues commonly associated with airlines such as baggage fee revenue, ticket change fee revenue and the marketing component of the sale of mileage credits are retained by the Company’s major airline partners on flights that the Company operates under its code-share agreements. The following summarizes the significant provisions of each code-share agreement the Company has with each major airline partner: Delta Connection Agreements Agreement Aircraft type Number of Aircraft Term / Termination SkyWest Airlines Delta Connection Agreement (fixed-fee arrangement)  CRJ 200  CRJ 700  CRJ 900  E175 50 27 36 13  Individual aircraft have scheduled removal dates under the agreement between 2017 and 2026  The average remaining term of the aircraft under contract is 3.7 years ExpressJet Delta Connection Agreement (fixed-fee arrangement)  CRJ 200  CRJ 700  CRJ 900 38 35 28  Individual aircraft have scheduled removal dates under the agreement between 2017 and 2022  The average remaining term of the aircraft under contract is 2.8 years SkyWest Airlines Delta Connection Prorate Agreement (revenue-sharing arrangement)  CRJ 200 21  Terminable with 30-day notice United Express Agreements Agreement Aircraft type Number of Aircraft Term / Termination SkyWest Airlines United Express Agreements (fixed-fee arrangement)  CRJ 200  CRJ 700  E175 53 35 58  Individual aircraft have scheduled removal dates under the agreement between 2017 and 2027  The average remaining term of the aircraft under contract is 5.7 years ExpressJet United ERJ Agreement (fixed-fee arrangement)  ERJ 145  ERJ 135 140 5  Individual aircraft have scheduled removal dates under the agreement during 2017, subject to two one-year extensions   The average remaining term of the aircraft under contract is 0.9 years SkyWest Airlines United Express Prorate Agreement (revenue-sharing arrangement)  CRJ 200 22  Terminable with 120-day notice American Agreements Agreement Aircraft type Number of Aircraft Term / Termination Dates SkyWest Airlines American Agreement (fixed-fee arrangement)  CRJ 200  CRJ 700 9 23  CRJ200 aircraft are scheduled to expire in 2017 and the CRJ700 aircraft are scheduled to expire in 2019 SkyWest Airlines American Prorate Agreement (revenue-sharing arrangement)  CRJ 200 6  Terminable with 120-day notice ExpressJet American Agreement (fixed-fee arrangement)  CRJ 200  CRJ 700  ERJ 145 11 10 14  CRJ200 aircraft are scheduled to expire in 2017 and the CRJ700 aircraft are scheduled to expire in 2020 ExpressJet American Prorate Agreement (revenue-sharing arrangement)  CRJ 200 3  Terminable with 120-day notice Alaska Capacity Purchase Agreement Agreement Aircraft type Number of Aircraft Term / Termination SkyWest Airlines Alaska Agreement (fixed-fee arrangement)  E175 15  Individual aircraft have scheduled removal dates under the agreement between 2027 and 2028 The Company anticipates placing an additional seven E175 aircraft with United, five additional E175 aircraft with Alaska and six E175 aircraft with Delta throughout 2017. The Company is scheduled to have 49 CRJ700 aircraft in service with American by mid-2017, all of which were previously operated in the existing fleet of other major airline partners. At the end of 2016, the Company had 213 CRJ200 aircraft and 159 ERJ145/135 aircraft in scheduled service. The Company anticipates it will reduce its CRJ200 aircraft by approximately 46 aircraft and its ERJ145/135 aircraft by approximately 59 aircraft during 2017. The Company also anticipates that ExpressJet will transition to flying primarily dual-class aircraft in its CRJ aircraft operation by removing its CRJ200 aircraft from service over the next year. Deferred Aircraft Credits The Company accounts for incentives provided by aircraft manufacturers as deferred credits. The deferred credits related to leased aircraft are amortized on a straight‑line basis as a reduction to rent expense over the lease term. Credits related to owned aircraft reduce the purchase price of the aircraft, which has the effect of amortizing the credits on a straight‑line basis as a reduction in depreciation expense over the life of the related aircraft. The incentives are credits that may be used to purchase spare parts and pay for training and other expenses. Income Taxes The Company recognizes a liability or asset for the deferred tax consequences of all temporary differences between the tax basis of assets and liabilities and their reported amounts in the consolidated financial statements that are expected to result in taxable or deductible amounts in future years when the reported amounts of the assets and liabilities are recovered or settled. Net Income (Loss) Per Common Share Basic net income (loss) per common share (“Basic EPS”) excludes dilution and is computed by dividing net income (loss) by the weighted average number of common shares outstanding during the period. Diluted net income (loss) per common share (“Diluted EPS”) reflects the potential dilution that could occur if stock options or other contracts to issue common stock were exercised or converted into common stock. The computation of Diluted EPS does not assume exercise or conversion of securities that would have an anti‑dilutive effect on net income (loss) per common share. During the years ended December 31, 2016, 2015 and 2014, 2,077,000, 505,000 and 3,191,000 shares reserved for issuance upon the exercise of outstanding options were excluded from the computation of Diluted EPS respectively, as the respective exercise price exceeded the weighted average fair market value of the Company’s stock for such year. The calculation of the weighted average number of common shares outstanding for Basic EPS and Diluted EPS are as follows for the years ended December 31, 2016, 2015 and 2014 (in thousands): Year Ended December 31, 2016 2015 2014 Numerator: Net Income (Loss) $ $ $ Denominator: Denominator for basic earnings per-share weighted average shares Dilution due to stock options and restricted stock units — — Denominator for diluted earnings per-share weighted average shares Basic earnings (loss) per-share $ $ $ Diluted earnings (loss) per-share $ $ $ Comprehensive Income (Loss) Comprehensive income (loss) includes charges and credits to stockholders’ equity that are not the result of transactions with the Company’s shareholders, including changes in unrealized appreciation (depreciation) on marketable securities. Comprehensive loss for the year ended December 31, 2014 included unrealized gain (loss) on foreign currency translation adjustment related to the Company’s equity investment in Trip Linhas Aéreas, a regional airline operating in Brazil (“TRIP”). Fair Value of Financial Instruments The carrying amounts reported in the consolidated balance sheets for receivables and accounts payable approximate fair values because of the immediate or short‑term maturity of these financial instruments. Marketable securities are reported at fair value based on market quoted prices in the consolidated balance sheets. If quoted prices in active markets are no longer available, the Company has estimated the fair values of these securities utilizing a discounted cash flow analysis as of December 31, 2016. These analyses consider, among other items, the collateralization underlying the security investments, the creditworthiness of the counterparty, the timing of expected future cash flows, and the expectation of the next time the security is expected to have a successful auction. The fair value of the Company’s long‑term debt is estimated based on current rates offered to the Company for similar debt and was approximately $2,566.5 million as of December 31, 2016, as compared to the carrying amount of $2,570.9 million as of December 31, 2016. The Company’s fair value of long‑term debt as of December 31, 2015 was $1,939.8 million as compared to the carrying amount of $1,948.8 million as of December 31, 2015. Segment Reporting Generally accepted accounting principles require disclosures related to components of a company for which separate financial information is available to, and regularly evaluated by, the Company’s chief operating decision maker when deciding how to allocate resources and in assessing performance. The Company’s three operating segments consist of the operations conducted by SkyWest Airlines, ExpressJet and SkyWest Leasing. Information pertaining to the Company’s reportable segments is presented in Note 2, Segment Reporting . Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update No. 2014-09, “Revenue from Contracts with Customers” (“ASU No. 2014-09”). Under ASU No. 2014-09, revenue is recognized at the time a good or service is transferred to a customer for the amount of consideration received for that specific good or service. In July 2015, the FASB deferred the effective date of ASU No. 2014-09 for annual reporting periods beginning after December 15, 2017. In 2016, the FASB issued several amendments to the standard, including principal versus agent considerations when another party is involved in providing goods or services to a customer and the application of identifying performance obligations. The Company continues to assess the potential impacts of ASU No. 2014-09 on its fixed-fee contracts, prorate flying agreements, ground handling agreements and other revenue transactions. The Company anticipates completing its review of the impact by the second quarter of 2017. Interpretations are on-going and could have a significant impact on the Company’s implementation. The Company believes the principal versus agent considerations may change how the Company presents revenue for certain directly-reimbursed expenses under its fixed-fee contracts, such as fuel expenses. ASU No. 2014-09 is required to be applied either full retrospective to each prior reporting period presented or modified retrospective with the cumulative effect of initially applying it at the date of initial application. The Company anticipates using the full retrospective method of adoption. In April 2015, the FASB issued Account Standards Update No. 2015-03, “Interest—Imputation of Interest: Simplifying the Presentation of Debt Issuance Costs,” which requires debt issuance costs related to a recognized debt liability to be presented as a direct deduction from the carrying amount of that debt liability. The new guidance only impacts financial statement presentation. The guidance was effective in the first quarter of 2016. The Company adopted this guidance January 1, 2016 on a retrospective basis. As a result, $20.9 million of unamortized debt issuance costs that had been included in the Other assets line on the consolidated balance sheets as of December 31, 2015 are now presented as direct deductions from the carrying amounts of the related debt liabilities. In November 2015, the FASB issued Accounting Standards Update 2015-17, “Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes” (“ASU No. 2015-17”). ASU No. 2015-17 requires that deferred tax liabilities and assets be classified as noncurrent in a classified statement of financial position. The current requirement that deferred tax liabilities and assets of a tax-paying component of an entity be offset and presented as a single amount is not affected by ASU No. 2015-17. ASU No. 2015-17 is effective for annual periods beginning after December 15, 2016, and interim periods within those annual periods. The Company’s management currently anticipates the impact of adopting ASU No. 2015-17 to result in reducing the Company’s current deferred tax asset to zero with corresponding resolution in the recorded amount of the Company’s long-term deferred tax liabilities. In February 2016, the FASB issued Accounting Standards Update 2016-02, “Leases (Topic 842)” (“ASU No. 2016-02”). ASU No. 2016-02 amends the existing accounting standards for lease accounting, including requiring lessees to recognize most leases on their balance sheets and making targeted changes to lessor accounting. ASU No. 2016-02 will be effective beginning in the first quarter of 2019. Early adoption of ASU No. 2016-02 is permitted. ASU No. 2016-02 requires a modified retrospective transition approach for all leases existing at, or entered into after, the date of initial application, with an option to use certain transition relief. The Company’s management is currently evaluating the impact the adoption of ASU 2016-02 is anticipated to have on the Company’s consolidated financial statements. In March 2016, the FASB issued Accounting Standards Update

Segment Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2016
Segment Reporting
Segment Reporting	(2) Segment Reporting Generally accepted accounting principles require disclosures related to components of a company for which separate financial information is available to, and regularly evaluated by, the Company’s chief operating decision maker when deciding how to allocate resources and in assessing performance. The Company’s three reporting segments consist of the operations of SkyWest Airlines, ExpressJet and SkyWest Leasing activities. Corporate overhead expenses incurred by the Company are allocated to the operating expenses of SkyWest Airlines and ExpressJet. The Company’s chief operating decision maker analyzes the profitability of operating the E175 aircraft (including operating costs and associated revenue) separately from the profitability of the Company’s ownership, financing costs and associated revenue of the Company’s E175 aircraft (including depreciation expense, interest expense and associated revenue). The SkyWest Leasing segment includes revenue attributed to the Company’s E175 aircraft ownership cost earned under the applicable fixed-fee contracts and the depreciation and interest expense of the Company’s E175 aircraft. The SkyWest Leasing segment’s total assets and capital expenditures include the acquired E175 aircraft. The SkyWest Leasing segment additionally includes the activity of two CRJ200 aircraft leased to a third party. The following represents the Company’s segment data for the years ended December 31, 2016, 2015 and 2014 (in thousands). Year Ended December 31, 2016 SkyWest Airlines ExpressJet SkyWest Leasing Consolidated Operating revenues $ $ $ $ Operating expense Depreciation and amortization expense Special items — Interest expense Segment profit (loss) (1) Identifiable intangible assets, other than goodwill — — Total assets Capital expenditures (including non-cash) Year Ended December 31, 2015 SkyWest Airlines ExpressJet SkyWest Leasing Consolidated Operating revenues $ $ $ $ Operating expense Depreciation and amortization expense Interest expense Segment profit (loss) (1) Identifiable intangible assets, other than goodwill — — Total assets Capital expenditures (including non-cash) Year Ended December 31, 2014 SkyWest Airlines ExpressJet SkyWest Leasing Consolidated Operating revenues $ $ $ $ Operating expense Depreciation and amortization expense Special items — Interest expense Segment profit (loss) (1) Identifiable intangible assets, other than goodwill — — Total assets Capital expenditures (including non-cash) (1) Segment profit is operating income less interest expense

Long-Term Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2016
Long-Term Debt
Long-Term Debt	(3) Long‑term Debt Long‑term debt consisted of the following as of December 31, 2016 and 2015 (in thousands): December 31, December 31, 2016 2015 Notes payable to banks, due in semi-annual installments, variable interest based on LIBOR, or with interest rates ranging from 2.64% to 2.82% through 2017 to 2020, secured by aircraft $ $ Notes payable to a financing company, due in semi-annual installments, variable interest based on LIBOR, or with interest rates ranging from 2.27% to 3.25% through 2017 to 2021, secured by aircraft Notes payable to banks, due in semi-annual installments plus interest at 6.06% to 6.51% through 2021, secured by aircraft Notes payable to a financing company, due in semi-annual installments plus interest at 5.78% to 6.23% through 2017, secured by aircraft Notes payable to banks, due in monthly installments plus interest of 2.68% to 6.86% through 2025, secured by aircraft Notes payable to banks, due in monthly installments, plus interest at 6.05% through 2020, secured by aircraft Notes payable to banks, due in monthly installments, plus interest at 3.44% through 2019, secured by aircraft Notes payable to banks, due in quarterly installments plus interest at 3.39% to 4.68% through 2028, secured by aircraft Notes payable to banks, due in monthly installments, plus interest based on LIBOR at 3.54% through 2017, secured by aircraft Notes payable to banks due in monthly installments, interest at 3.30% through 2019, secured by spare engines Long-term debt $ $ Less current maturities Long-term debt, net of current maturities $ $ The Company adopted guidance ASU 2015-03 on January 1, 2016. As a result, the unamortized debt issuance costs that had been included in Other assets line on the consolidated balance sheets as of December 31, 2015 are now presented as direct deductions from the carrying amounts of the related debt liabilities as shown below as of December 31, 2016 and 2015 (see Note 1 Nature of Operations and Summary of Significant Accounting Policies ) (in thousands): December 31, 2016 December 31, 2015 Current portion long-term debt $ $ Long-term debt net of current maturities Total long-term debt (including current portion) $ $ Unamortized debt issue cost, net Total long-term debt, net of debt issue costs $ $ During the year ended December 31, 2016, the Company acquired 41 new E175 aircraft. Approximately 85% of the aircraft purchase price was financed through the issuance of debt and 15% of the aircraft purchase price was paid with cash. As of December 31, 2016 and 2015, the Company had $2.6 billion and $1.9 billion, respectively, of long‑term debt obligations primarily related to the acquisition of aircraft and certain spare engines. The average effective interest rate on the debt related to those long-term debt obligations at December 31, 2016 and 2015, was approximately 3.8% and 3.7%, respectively. During the year ended December 31, 2016, the Company used $16.5 million in cash to extinguish $18.4 million in debt early. The payment resulted in a pre-tax gain of $1.3 million, reflected as other income in the consolidated statements of comprehensive income (loss). During the year ended December 31, 2015, the Company used $110.8 million in cash to pay off $145.4 million in debt. The payment resulted in a pre-tax gain of $33.7 million, reflected as other income in the consolidated statements of comprehensive income (loss). The aggregate amounts of principal maturities of long‑term debt as of December 31, 2016 were as follows (in thousands): 2017 $ 2018 2019 2020 2021 Thereafter $ During the year ended December 31, 2016, the Company increased its line of credit with a bank from $25 million to $75 million. The line of credit includes minimum liquidity and profitability covenants and is secured by certain assets. As of December 31, 2016, the Company was in compliance with the line of credit covenants and had no borrowings outstanding under the facility. However, at December 31, 2016, the Company had $6.5 million in letters of credit issued under the facility which reduced the amount available under the facility to $68.5 million. The facility expires on June 1, 2018 and has a variable interest rate of LIBOR plus 2.5% (3.3% at December 31, 2016). As of December 31, 2016 and 2015, the Company had $87.7 million and $88.9 million, respectively, in letters of credit and surety bonds outstanding with various banks and surety institutions.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2016
Income Taxes
Income Taxes	(4) Income Taxes The provision for income taxes includes the following components (in thousands): Year ended December 31, 2016 2015 2014 Current tax provision (benefit): Federal $ $ $ State Foreign — Deferred tax provision (benefit): Federal State Provision for income taxes $ $ $ The following is a reconciliation between the statutory federal income tax rate of 35% and the effective rate which is derived by dividing the provision for income taxes by income (loss) before for income taxes (in thousands): Year ended December 31, 2016 2015 2014 Computed provision (benefit) for income taxes at the statutory rate $ $ $ Increase (decrease) in income taxes resulting from: State income tax provision (benefit), net of federal income tax benefit Non-deductible expenses Valuation allowance changes affecting the provision for income taxes Foreign income taxes, net of federal & state benefit — — Other, net Provision for income taxes $ $ $ For the year ended December 31, 2016, the Company recorded a $0.8 million valuation allowance against certain deferred tax assets primarily associated with ExpressJet state net operating losses with a limited carry forward period. The release of the valuation allowance was based on changes in state tax laws and the Company's income tax projections which reduced the amount of deferred tax assets that are anticipated to expire before the deferred tax assets may be utilized. For the year ended December 31, 2015, the Company released a $0.9 million valuation allowance against certain deferred tax assets primarily associated with ExpressJet state net operating losses with a limited carry forward period. The release of the valuation allowance was based on the Company's other income related to early retirement of certain long term debt which reduced the amount of deferred tax assets that are anticipated to expire before the deferred tax assets may be utilized. For the year ended December 31, 2014, the Company recorded a $6.0 million valuation allowance against certain deferred tax assets primarily associated with ExpressJet state net operating losses with a limited carry forward period. The valuation was based on the Company's assessment of deferred tax assets that are anticipated to expire before the deferred tax assets may be utilized. The Company also recorded a $2.0 million foreign tax expense associated with Brazilian withholding tax on the sale of the Company's equity interest in TRIP. The significant components of the Company’s net deferred tax assets and liabilities as of December 31, 2015 and 2014 are as follows (in thousands): As of December 31, 2016 2015 Deferred tax assets: Intangible asset $ $ Accrued benefits Net operating loss carryforward AMT credit carryforward Deferred aircraft credits Accrued reserves and other Total deferred tax assets Valuation allowance Deferred tax liabilities: Accelerated depreciation Total deferred tax liabilities Net deferred tax liability $ $ The Company’s deferred tax liabilities were primarily generated through accelerated depreciation, combined with shorter depreciable tax lives, allowed under the IRS tax code for purchased aircraft and support equipment compared to the Company’s U.S. Generally Accepted Accounting Principles ("GAAP") depreciation policy for such assets using the straight-line method (see Note 1 Nature of Operations and Summary of Significant Accounting Policies ). The Company's valuation allowance is related to certain deferred tax assets with a limited carry forward period. The Company does not anticipate utilizing these deferred tax assets prior to the lapse of the carry forward period. At December 31, 2016 and 2015, the Company had federal net operating losses of approximately $763.9 million and $189.0 million and state net operating losses of approximately $469.2 million and $352.2 million, respectively. The estimated effective tax rate applicable to the state and federal net operating losses as of December 31, 2016 was 35.0% and 2.6%, respectively. The Company anticipates that the federal and state net operating losses will start to expire in 2027 and 2017, respectively. The Company has recorded a valuation allowance for state net operating losses the Company anticipates will expire before the benefit will be realized due to the limited carry forward periods. As of December 31, 2016 and 2015, the Company also had an alternative minimum tax credit of approximately $17.6 million and $21.4 million, respectively, which does not expire .

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies
Commitments and Contingencies	(5) Commitments and Contingencies Lease Obligations The Company leases 415 aircraft, as well as airport facilities, office space, and various other property and equipment under non‑cancelable operating leases which are generally on a long‑term net rent basis where the Company pays taxes, maintenance, insurance and certain other operating expenses applicable to the leased property. The following table summarizes future minimum rental payments required under operating leases that have non‑cancelable lease terms as of December 31, 2016 (in thousands): 2017 $ 2018 2019 2020 2021 Thereafter $ The majority of the Company’s leased aircraft are owned and leased through trusts whose sole purpose is to purchase, finance and lease these aircraft to the Company; therefore, they meet the criteria of a variable interest entity. However, since these are single owner trusts in which the Company does not participate, the Company is not considered at risk for losses and is not considered the primary beneficiary. As a result, the Company has not consolidated any of these trusts or any other entities in applying the accounting guidance. The Company’s management believes that the Company’s maximum exposure under these leases is the remaining lease payments. The Company’s leveraged lease agreements typically obligate the Company to indemnify the equity/owner participant against liabilities that may arise due to changes in benefits from tax ownership of the respective leased aircraft. The terms of these contracts range up to nine years. The Company did not accrue any liability relating to the indemnification to the equity/owner participant because of management’s assessment that the probability of this occurring is remote. Total rental expense for non-cancelable aircraft operating leases was approximately $262.6 million, $273.7 million and $305.3 million for the years ended December 31, 2016, 2015 and 2014, respectively. The minimum rental expense for airport station rents was approximately $31.4 million, $35.1 million and $29.0 million for the years ended December 31, 2016, 2015 and 2014, respectively. Self‑insurance The Company self‑insures a portion of its potential losses from claims related to workers’ compensation, environmental issues, property damage, medical insurance for employees and general liability. Losses are accrued based on an estimate of the ultimate aggregate liability for claims incurred, using standard industry practices and the Company’s actual experience. Actual results could differ from these estimates. Legal Matters The Company is subject to certain legal actions which it considers routine to its business activities. As of December 31, 2016, management believed, after consultation with legal counsel, that the ultimate outcome of such legal matters was not likely to have a material adverse effect on the Company’s financial position, liquidity or results of operations. Concentration Risk and Significant Customers The Company requires no collateral from its major airline partners or customers, but monitors the financial condition of its major airline partners. Under the majority of the Company’s code-share agreements, the Company receives weekly payments from its major code-share partners that approximate a significant percentage of the compensation earned for such period. Additionally, the Company provides certain customer service functions at multiple airports for various airlines and the Company maintains an allowance for doubtful accounts receivable based upon expected collectability of all accounts receivable. The Company’s allowance for doubtful accounts totaled $173,000 and $187,000 as of December 31, 2016 and 2015, respectively. For the years ended December 31, 2016, 2015 and 2014, the Company’s contractual relationships with Delta and United combined accounted for approximately 85.4%, 86.9% and 88.7%, respectively of the Company’s total revenues. Employees Under Collective Bargaining Agreements As of December 31, 2016, the Company had approximately 16,900 full‑time equivalent employees. Approximately 33.4% of these employees were represented by unions, including the following employee groups. Notwithstanding the completion of the ExpressJet Combination, ExpressJet’s employee groups continue to be represented by those unions who provided representation prior to the ExpressJet Combination. Accordingly, the following table refers to ExpressJet’s employee groups based upon their union affiliations prior to the ExpressJet Combination. Approximate Number of Active Employees Status of Employee Group Represented Representatives Agreement Atlantic Southeast Pilots Air Line Pilots Association International Amendable February 2018 Atlantic Southeast Flight Attendants International Association of Machinists and Aerospace Workers Currently Amendable Atlantic Southeast Flight Controllers Transport Workers Union of America Currently Amendable Atlantic Southeast Mechanics International Brotherhood of Teamsters Currently Amendable Atlantic Southeast Stock Clerks International Brotherhood of Teamsters Currently Amendable ExpressJet Delaware Pilots Air Line Pilots Association International Amendable February 2018 ExpressJet Delaware Flight Attendants International Association of Machinists and Aerospace Workers Currently Amendable ExpressJet Delaware Mechanics International Brotherhood of Teamsters Currently Amendable ExpressJet Delaware Dispatchers Transport Workers Union of America Currently Amendable ExpressJet Delaware Stock Clerks International Brotherhood of Teamsters Currently Amendable In February 2016, the Atlantic Southeast Pilots and the ExpressJet Delaware Pilots ratified a two-year contract extension to their respective labor agreements.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2016
Fair Value Measurements
Fair Value Measurements	(6) Fair Value Measurements The Company holds certain assets that are required to be measured at fair value in accordance with GAAP. The Company determined fair value of these assets based on the following three levels of inputs: Level 1 —Quoted prices in active markets for identical assets or liabilities. Level 2 —Observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Some of the Company’s marketable securities primarily utilize broker quotes in a non‑active market for valuation of these securities. Level 3 —Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities, therefore requiring an entity to develop its own assumptions. As of December 31, 2016, the Company held certain assets that are required to be measured at fair value on a recurring basis. Assets measured at fair value on a recurring basis are summarized below (in thousands): Fair Value Measurements as of December 31, 2016 Total Level 1 Level 2 Level 3 Marketable Securities Bonds and bond funds $ $ — $ $ — Commercial paper — — Asset backed securities $ $ — $ $ — Cash, Cash Equivalents and Restricted Cash — — Total Assets Measured at Fair Value $ $ $ $ — Fair Value Measurements as of December 31, 2015 Total Level 1 Level 2 Level 3 Marketable Securities Bonds and bond funds $ $ — $ $ — Commercial paper — — Asset backed securities $ $ — $ $ — Cash, Cash Equivalents and Restricted Cash — — Auction Rate Securities(a) — — Total Assets Measured at Fair Value $ $ $ $ (a) Auction rate securities included in long-term “Other assets” in the Consolidated Balance Sheet Based on market conditions, the Company used a discounted cash flow valuation methodology for auction rate securities. Accordingly, for purposes of the foregoing consolidated financial statements, these securities were categorized as Level 3 securities. The Company’s “Marketable Securities” classified as Level 2 primarily utilize broker quotes in a non‑active market for valuation of these securities. No significant transfers between Level 1, Level 2 and Level 3 occurred during the year ended December 31, 2016. The Company’s policy regarding the recording of transfers between levels is to record any such transfers at the end of the reporting period. The following table presents the Company’s assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3) at December 31, 2016 (in thousands): Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Auction Rate Securities Balance at January 1, 2016 $ Total realized and unrealized gains or (losses) Included in earnings Included in other comprehensive income Transferred out — Settlements Balance at December 31, 2016 $ —

Investment in Other Companies

Investment in Other Companies	12 Months Ended
	Dec. 31, 2016
Investment in Other Companies
Investment in Other Companies	(7) Investment in Other Companies In 2014, the Company completed the sale of its 20% interest in TRIP to Trip investments Ltda (“Trip Investimentos”) for $42 million. The Company recorded a gain from the sale of its TRIP shares of $24.9 million during the year ended December 31, 2014, which is reflected in Other Income in the Consolidated Statements of Comprehensive Income (Loss).

Special Items

Special Items	12 Months Ended
	Dec. 31, 2016
Special Items
Special Items	(8) Special Items In December 2016, the Company decided to remove CRJ200 aircraft from ExpressJet’s operation. In connection therewith, the Company plans to remove approximately 46 CRJ200 aircraft from its fleet during 2017. Additionally, in December 2016, the Company entered into a termination agreement covering RVG agreements on 76 CRJ200 aircraft owned by SkyWest Airlines and ExpressJet whereby it agreed to terminate Bombardier’s future RVG commitment in exchange for a cash payment and other consideration valued at $125 million. The agreement also eliminated the Company's future requirement to return the aircraft to a mid-time maintenance condition and certain remarketing activities. This termination agreement allowed for the acceleration of the retirement of the CRJ 200 fleet. As a result of the scheduled reduction in the CRJ200 fleet in 2017, the termination of the RVG agreements with Bombardier and the current market values of its CRJ200 aircraft excluding Bombardier’s RVGs, the Company concluded that indicators of impairment existed and therefore, evaluated its CRJ200 fleet and related assets for impairment. Pursuant to ASC 360-10, “Impairment and Disposal of Long-Lived Assets,” the Company determined that with respect to the CRJ200 aircraft, separate asset groups existed based on the various major partner contracts. A recoverability test was performed utilizing estimated undiscounted future cash flows for each asset group pursuant to applicable contracts with the major partners and forecasted cash flow including the estimated value the Company would realize upon disposal of aircraft. This was compared to the carrying value of the related assets resulting in a cash flow deficiency indicating that an impairment existed. The impairment analysis required the Company to perform an assessment of the fair value of its long-lived assets related to the CRJ200 aircraft within the asset groups utilized in the recoverability test. The Company engaged a third party to assist in determining the fair value of certain of the long-lived assets, including the aircraft, spare engines and fixed asset spare parts inventory. These values were estimated based on listed market values or recent third-party market transactions for similar assets, and considering the related maintenance status of the fleet. Additionally, the Company estimated the fair value of certain long-lived prepaid lease assets using the net present value of estimated current CRJ200 lease rates. All fair values are considered to be Level 3 within the fair value hierarchy. The amounts the Company may ultimately realize from the disposal of its CRJ200 long-lived assets may vary from the December 31, 2016 fair value assessments. Additionally, the Company’s fixed-fee contract with United covering certain of the ERJ145 aircraft is scheduled to expire at the end of 2017, subject to United’s two one-year extension rights intended to facilitate an orderly return of ERJ145 aircraft to United. The ERJ145 aircraft are leased from United and the Company is obligated to return the aircraft to United as each aircraft is scheduled to terminate under the contract. There are no significant unreimbursed return related costs associated with these lease returns. Under the terms of the fixed-fee contract, the Company anticipates removing approximately 45 ERJ145s from its fleet in 2017 and returning the aircraft to United. Due to the uncertainty regarding the probability of extending the ERJ145 fixed-fee arrangement with United beyond the existing terms, the Company evaluated the ERJ145 asset group for impairment including spare engines and related spare parts inventory. The Company engaged a third party to assist in determining the fair value of the spare parts engines and inventory. The spare engines and inventory were valued based on recent market transactions for similar assets. All fair values are considered to be Level 3 within the fair value hierarchy. The amounts the Company may ultimately realize from the disposal of its ERJ145 long-lived assets may vary from the December 31, 2016 fair value assessments. The following table summarizes the components of the Company's special items, for the year ended December 31, 2016, 2015 and 2014 (in thousands): Year ended December 31, 2016 2015 2014 Special items: CRJ200 aircraft related items 1 $ $ — $ — EMB120 aircraft related items 2 — — ERJ145 aircraft related items 3 — Paint facility and related items 4 — — Total special items $ $ — $ (1) Consists primarily of inventory valuation charges and impairment charges to write-down CRJ200 aircraft including related long-lived assets to their estimated fair value. The estimated fair value of the long-lived assets, including the aircraft and fixed asset spare parts inventory, was based on third party appraisals on the assets. These values were estimated based on listed market values or recent third-party market transactions for similar assets. Additionally, the Company estimated the fair value of certain long-lived prepaid lease assets using the net present value of estimated current CRJ200 lease rates. All fair values are considered to be Level 3 within the fair value hierarchy. Of the special items $184.3 million related to SkyWest Airlines and $240.2 million related to ExpressJet. These charges are net of $90 million in cash proceeds and other considerations from the Bombardier termination agreement. These special items are reflected in the SkyWest Airlines and ExpressJet operating expenses under Note 2 Segment Reporting. (2) Consists primarily of impairment charges to write-down owned EMB120 aircraft including capitalized engine overhaul costs, and related long-lived assets to their estimated fair value and accrued obligations on leased aircraft and related costs. The estimated fair value of the long-lived assets was based on third party valuations for similar assets which is considered an unobservable input (Level 3) under the fair value hierarchy. In November 2014, the Company approved a plan to discontinue operating the EMB120 aircraft by the end of the second quarter of 2015. The decision to discontinue use of the EMB120 aircraft included management’s assessment of the need for pilots to operate upcoming deliveries for the E175 aircraft, the incremental training cost to hire new pilots compared to retraining existing EMB120 pilots to operate CRJ or E175 aircraft, and the uncertainty related to the number of qualified pilots available for hire, combined with the overall age and increased operating costs of the Company’s EMB120 fleet. These special items are reflected in the SkyWest Airlines operating expenses under Note 2 Segment Reporting. (3) The ERJ145 aircraft related items recorded in the 2016 special charge consist primarily of inventory valuation charges and impairment charges to write-down certain ERJ145 long-lived assets, which primarily consisted of spare engines and ERJ145 spare aircraft parts, to their estimated fair value of $41.2 million. The estimated fair value of the long-lived assets was based on third party appraisals and valuations for similar assets which is considered an unobservable input (Level 3) under the fair value hierarchy. These special items are reflected in the ExpressJet operating expenses under Note 2 Segment Reporting . The ERJ145 aircraft related items recorded in the 2014 special charge consist primarily of impairment charges to write-down certain ERJ145 long-lived assets, which primarily consisted of spare engines and ERJ145 spare aircraft parts, to their estimated fair value of $11.4 million and accrued obligations on leased aircraft and related costs of $1.5 million. The estimated fair value of the long-lived assets was based on third party valuations for similar assets which is considered an unobservable input (Level 3) under the fair value hierarchy. These special items are reflected in the ExpressJet operating expenses under Note 2 Segment Reporting . (4) Consists primarily of the write-down of assets associated with the disposition of the Company’s paint facility located in Saltillo, Mexico, which was sold during the year ended December 31, 2014. These special items are reflected in the ExpressJet operating expenses under Note 2 Segment Reporting .

Capital Transactions

Capital Transactions	12 Months Ended
	Dec. 31, 2016
Capital Transactions
Capital Transactions	(9) Capital Transactions Preferred Stock The Company is authorized to issue 5,000,000 shares of preferred stock in one or more series without shareholder approval. No shares of preferred stock are presently outstanding. The Company’s Board of Directors is authorized, without any further action by the shareholders of the Company, to (i) divide the preferred stock into series; (ii) designate each such series; (iii) fix and determine dividend rights; (iv) determine the price, terms and conditions on which shares of preferred stock may be redeemed; (v) determine the amount payable to holders of preferred stock in the event of voluntary or involuntary liquidation; (vi) determine any sinking fund provisions; and (vii) establish any conversion privileges. Stock Compensation On May 4, 2010, the Company’s shareholders approved the adoption of the SkyWest, Inc. 2010 Long‑Term Incentive Plan, which provides for the issuance of up to 5,150,000 shares of common stock to the Company’s directors, employees, consultants and advisors (the “2010 Incentive Plan”). The 2010 Incentive Plan provides for awards in the form of options to acquire shares of common stock, stock appreciation rights, restricted stock grants, restricted stock units and performance awards. The 2010 Incentive Plan is administered by the Compensation Committee of the Company’s Board of Directors (the “Compensation Committee”), which is authorized to designate option grants as either incentive stock options for income tax purposes (“ISO”) or non-statutory stock options ISOs are granted at not less than 100% of the market value of the underlying common stock on the date of grant. Non‑statutory stock options are granted at a price as determined by the Compensation Committee. The fair value of stock options awarded under the Company’s stock option plans has been estimated as of the grant date using the Black‑Scholes option pricing model. The Company uses historical data to estimate option exercises and employee termination in the option pricing model. The expected term of options granted is derived from the output of the option pricing model and represents the period of time that options granted are expected to be outstanding. The expected volatilities are based on the historical volatility of the Company’s traded stock and other factors. The Company granted 206,021, 267,433 and 255,503 stock options to employees under the 2010 Incentive Plan during the years ended December 31, 2016, 2015 and 2014, respectively. Stock options granted in 2015 and 2016 vest in three equal installments over a three-year period. Stock options granted in 2014 have three-year cliff vesting periods. The following table shows the assumptions used and weighted average fair value for grants in the years ended December 31, 2016, 2015 and 2014. 2016 2015 2014 Expected annual dividend rate % % % Risk-free interest rate % % % Average expected life (years) Expected volatility of common stock Forfeiture rate % % % Weighted average fair value of option grants $ $ $ The Company recorded share‑based compensation expense only for those options that are expected to vest. The estimated fair value of the stock options is amortized over the vesting period of the respective stock option grants. During the year ended December 31, 2016, the Company granted 380,358 restricted stock units to certain of the Company’s employees under the 2010 Incentive Plan. The restricted stock units granted during the year ended December 31, 2016 have a three‑year cliff-vesting period, during which the recipient must remain employed with the Company or its subsidiaries. The weighted average fair value of the restricted stock units at the date of grants made during the year ended December 31, 2016 was $14.81 per share. The following table summarizes the activity of restricted stock units granted to certain Company employees as of December 31, 2016, 2015 and 2014: During the year ended December 31, 2016, the Company granted 380,358 shares of restricted stock units to certain Company’s employees under the 2010 Incentive Plan. The restricted stock units granted during the year ended December 31, 2016 have a three‑year vesting period, during which the recipient must remain employed with the Company or its subsidiaries. The weighted average fair value of the restricted stock units the date of grants made during the year ended December 31, 2016 was $14.81 per share. The following table summarizes the activity of restricted stock units granted to certain Company employees as of December 31, 2016, 2015 and 2014: Weighted-Average Grant-Date Fair Number of Shares Value Non-vested shares outstanding at December 31, 2013 $ Granted Vested Cancelled Non-vested shares outstanding at December 31, 2014 Granted Vested Cancelled Non-vested shares outstanding at December 31, 2015 Granted Vested Cancelled Non-vested shares outstanding at December 31, 2016 $ During the year ended December 31, 2016, the Compensation Committee granted performance share units, which are performance based restricted stock units, to certain Company employees with three-year performance based financial metrics that the Company must meet before those awards may be earned and the performance period for those grants ends December 31, 2018. The Compensation Committee will determine the achievement of performance results and corresponding vesting of performance shares for each performance period. At the end of each performance period, the number of shares awarded can range from 0% to 150% of the original granted amount, depending on the performance against the pre-established targets. The following table summarizes the activity of performance share units granted at target as of December 31, 2016. Weighted-Average Grant-Date Fair Number of Shares Value Non-vested shares outstanding at December 31, 2014 — $ — Granted Vested — — Cancelled Non-vested shares outstanding at December 31, 2015 $ Granted Vested — — Cancelled Non-vested shares outstanding at December 31, 2016 $ During the years ended December 31, 2016, 2015 and 2014 the Company granted fully‑vested shares of common stock to the Company’s directors in the amounts of 42,624, 36,950 and 44,631 shares, respectively, with a weighted average grant‑date fair value of $14.78, $14.05, and $12.10, respectively. During the year ended December 31, 2016, 2015 and 2014, the Company recorded equity‑based compensation expense of $7.6 million, $5.4 million and $5.3 million, respectively. As of December 31, 2016, the Company had $9.7 million of total unrecognized compensation cost related to non‑vested stock options, non‑vested restricted stock grants and non-vested performance stock units. Total unrecognized compensation cost will be adjusted for future changes in estimated forfeitures. The Company expects to recognize this cost over a weighted average period of 1.7 years. Options are exercisable for a period as defined by the Compensation Committee on the date granted; however, no stock option will be exercisable before six months have elapsed from the date it is granted and no stock option shall be exercisable after seven years from the date of grant. The following table summarizes the stock option activity for all of the Company’s plans for the years ended December 31, 2016, 2015 and 2014: 2016 2015 2014 Weighted Weighted Average Aggregate Weighted Weighted Average Remaining Intrinsic Average Average Number of Exercise Contractual Value Number of Exercise Number of Exercise Options Price Term ($000) Options Price Options Price Outstanding at beginning of year $ years $ $ $ Granted Exercised Cancelled Outstanding at end of year years $ Exercisable at December 31, 2016 years $ Exercisable at December 31, 2015 years $ The total intrinsic value of options to acquire shares of the Company’s common stock that were exercised during the years ended December 31, 2016, 2015 and 2014 was $4,250,000, $1,800,000 and $30,000, respectively. The following table summarizes the status of the Company’s non‑vested stock options as of December 31, 2016: Weighted-Average Number of Grant-Date Shares Fair Value Non-vested shares at beginning of year $ Granted Vested Cancelled Non-vested shares at end of year $ The following table summarizes information about the Company’s stock options outstanding at December 31, 2016: Options Outstanding Options Exercisable Weighted Average Number Remaining Weighted Average Number Weighted Average Range of Exercise Prices Outstanding Contractual Life Exercise Price Exercisable Exercise Price $8 to $11 years $ — $ — $12 to $14 years $15 to $19 years $8 to $19 years $ $ Taxes The Company’s treatment of stock option grants of non‑qualified options, restricted stock units and performance shares results in the creation of a deferred tax asset, which is a temporary difference, until the time that the option is exercised or the restrictions lapse.

Retirement Plans and Employee S

Retirement Plans and Employee Stock Purchase Plans	12 Months Ended
	Dec. 31, 2016
Retirement Plans and Employee Stock Purchase Plans
Retirement Plans and Employee Stock Purchase Plans	(10) Retirement Plans and Employee Stock Purchase Plans SkyWest Retirement Plan The Company sponsors the SkyWest, Inc. Employees’ Retirement Plan (the “SkyWest Plan”). Employees who have completed 90 days of service and are at least 18 years of age are eligible for participation in the SkyWest Plan. Employees may elect to make contributions to the SkyWest Plan. Generally, the Company matches 100% of such contributions up to 2%, 4% or 6% of the individual participant’s compensation, based upon length of service for non-pilot employees and up to 3%, 5% or 7% of the individual participant’s compensation, based upon length of service for pilot employees. Additionally, a discretionary contribution may be made by the Company. The Company’s combined contributions to the SkyWest Plan were $23.2 million, $20.4 million and $19.3 million for the years ended December 31, 2016, 2015 and 2014, respectively. ExpressJet and Atlantic Southeast Retirement Plans ExpressJet (formerly Atlantic Southeast) sponsors the Atlantic Southeast Airlines, Inc. Investment Savings Plan (the “Atlantic Southeast Plan”). Employees who have completed 90 days of service and are 18 years of age are eligible for participation in the Atlantic Southeast Plan. Employees may elect to make contributions to the Atlantic Southeast Plan; however, ExpressJet limits the amount of company match at 6% of each participant’s total compensation, except for those with ten or more years of service whose company match is limited to 8% of total compensation. Additionally, ExpressJet matches the individual participant’s contributions from 20% to 75%, depending on the length of the participant’s service. Additionally, participants are 100% vested in their elective deferrals and rollover amounts and from 10% to 100% vested in company matching contributions based on length of service. ExpressJet additionally sponsors the ExpressJet Airlines, Inc. 401(k) Savings Plan (the “ExpressJet Retirement Plan”). Substantially all of ExpressJet’s domestic employees were covered by this plan at the time the Company acquired ExpressJet in 2010. Effective January 1, 2009, the ExpressJet Retirement Plan was amended such that certain matching payment amounts have been reduced or eliminated depending on the terms of the collective bargaining unit or work group, as applicable. ExpressJet’s contribution to the Atlantic Southeast and the ExpressJet Retirement Plans was $21.0 million, $24.0 million and $27.2 million for the years ended December 31, 2016, 2015 and 2014, respectively. Employee Stock Purchase Plans In May 2009, the Company’s Board of Directors approved the SkyWest, Inc. 2009 Employee Stock Purchase Plan (the “2009 Stock Purchase Plan”). All employees who have completed 90 days of employment with the Company or one of its subsidiaries are eligible to participate in the 2009 Stock Purchase Plan, except employees who own five percent or more of the Company’s common stock. The 2009 Stock Purchase Plan enables employees to purchase shares of the Company’s common stock at a five percent discount, through payroll deductions. Employees can contribute up to 15% of their base pay, not to exceed $25,000 each calendar year, for the purchase of shares. Shares are purchased semi-annually at a five percent discount based on the end of the period price. Employees can terminate their participation in the 2009 Stock Purchase Plan at any time upon written notice. The following table summarizes purchases made under the 2009 Employee Stock Purchase Plans during the years ended December 31, 2016, 2015 and 2014: Year ended December 31, 2016 2015 2014 Number of shares purchased Average price of shares purchased $ $ $ The 2009 Stock Purchase Plan is a non‑compensatory plan under the accounting guidance. Therefore, no compensation expense was recorded for the years ended December 31, 2016, 2015 and 2014.

Stock Repurchase

Stock Repurchase	12 Months Ended
	Dec. 31, 2016
Stock Repurchase
Stock Repurchase	(11) Stock Repurchase The Company’s Board of Directors has previously authorized the repurchase of the Company’s common stock in the public market. The Company did not repurchase any shares of its common stock during the year ended December 31, 2016. During the years ended December 31, 2015 and 2014, the Company repurchased 1.3 million and 0.7 million shares of common stock for approximately $18.7 million and $8.4 million, respectively at a weighted average price per share of $14.98 and $12.54, respectively. Subsequent to December 31, 2016, the Company’s Board of Directors authorized $100 million for additional repurchases of the Company’s common stock over a three year period.

Related-Party Transactions

Related-Party Transactions	12 Months Ended
	Dec. 31, 2016
Related-Party Transactions
Related-Party Transactions	(12) Related‑Party Transactions The Company’s Chairman of the Board and former Chief Executive Officer, serves on the Board of Directors of Zions Bancorporation (“Zions”). The Company maintains a line of credit (see Note 3) and certain bank and investment accounts with Zions. Zions is an equity participant in leveraged leases on one CRJ200 and two CRJ700 aircraft leased by the Company’s subsidiaries. Zions also refinanced five CRJ200 and two CRJ700 aircraft in 2012 for terms of five years, becoming the debtor on these aircraft. Zions also serves as the Company’s transfer agent. The Company’s cash balance in the accounts held at Zions as of December 31, 2016 and 2015 was $116.0 million and $65.0 million, respectively. The Company’s investment balance in the accounts held at Zions as of December 31, 2016 and 2015 was $121.6 million and $0, respectively. During the year ended December 31, 2016, the Company purchased $244,540 of spare aircraft parts from an entity affiliated with a director of the Company.

Quarterly Financial Data (Unaud

Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Data (Unaudited)
Quarterly Financial Data (Unaudited)	(13) Quarterly Financial Data (Unaudited) Unaudited summarized financial data by quarter for 2016 and 2015 is as follows (in thousands, except per share data): Year ended December 31, 2016 First Second Third Fourth Quarter Quarter Quarter Quarter Year Operating revenues $ $ $ $ $ Operating income Net income (loss)(1) Net income (loss) per common share: Basic Diluted Weighted average common shares: Basic: Diluted: Year ended December 31, 2015 First Second Third Fourth Quarter Quarter Quarter Quarter Year Operating revenues $ $ $ $ $ Operating income Net income Net income per common share: Basic Diluted Weighted average common shares: Basic: Diluted: (1) Operating loss for the fourth quarter of 2016 included a special charge of $465.6 million related to an impairment on the Company’s 50-seat aircraft.

SCHEDULE II_VALUATION AND QUALI

SCHEDULE II—VALUATION AND QUALIFYING ACCOUNTS	12 Months Ended
	Dec. 31, 2016
SCHEDULE II—VALUATION AND QUALIFYING ACCOUNTS
SCHEDULE II—VALUATION AND QUALIFYING ACCOUNTS	SKYWEST, INC. AND SUBSIDIARIES SCHEDULE II—VALUATION AND QUALIFYING ACCOUNTS For the Years Ended December 31, 2016, 2015 and 2014 (Dollars in thousands) Additions Balance at Charged to Beginning Costs and Balance at Description of Year Expenses Deductions End of Year Year ended December 31, 2016: Allowance for inventory obsolescence(1) $ $ $ — $ Allowance for doubtful accounts receivable — $ $ $ $ Year ended December 31, 2015: Allowance for inventory obsolescence $ $ $ — $ Allowance for doubtful accounts receivable — $ $ $ $ Year ended December 31, 2014: Allowance for inventory obsolescence $ $ $ — $ Allowance for doubtful accounts receivable — $ $ $ — $ (1) The increase in the inventory obsolescence related to additional excess inventory identified as part of the impairment analysis of the 50-seat aircraft. See note 8, Special items , for additional detail on the impairment.

Nature of Operations and Summ22

Nature of Operations and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Nature of Operations and Summary of Significant Accounting Policies
Basis of Presentation	Basis of Presentation The Company’s consolidated financial statements include the accounts of the Company and the SkyWest Airlines, ExpressJet and SkyWest Leasing segments, with all inter‑company transactions and balances having been eliminated. In preparing the accompanying consolidated financial statements, the Company has reviewed, as determined necessary by the Company’s management, events that have occurred after December 31, 2016, through the filing date of the Company’s annual report with the U.S. Securities and Exchange Commission. The Company reclassified certain prior period amounts to conform to the current period presentation.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three months or less to be cash equivalents. The Company classified $8.2 million of cash as restricted cash collateralizing letters of credit under the Company’s workers’ compensation insurance policy and classified it accordingly in the consolidated balance sheets as of December 31, 2016 and 2015.
Marketable Securities	Marketable Securities The Company’s investments in marketable debt and equity securities are deemed by management to be available-for-sale and are reported at fair market value with the net unrealized appreciation (depreciation) reported as a component of accumulated other comprehensive income (loss) in stockholders’ equity. At the time of sale, any realized appreciation or depreciation, calculated by the specific identification method, is recognized in other income and expense. The Company’s position in marketable securities as of December 31, 2016 and 2015 was as follows (in thousands): Gross unrealized Gross unrealized At December 31, 2016 Amortized Cost holding gains holding losses Fair market value Total cash and cash equivalents $ $ — $ — $ Available-for-sale securities: Bond and bond funds $ $ — $ $ Asset backed securities — — Total available-for-sale securities $ $ — $ $ Total cash and cash equivalents and available for sale securities $ $ — $ $ Gross unrealized Gross unrealized At December 31, 2015 Amortized Cost holding gains holding losses Fair market value Total cash and cash equivalents $ $ — $ — $ Available-for-sale securities: Bond and bond funds $ $ — $ $ Asset backed securities — Total available-for-sale securities $ $ $ $ Total cash and cash equivalents and available for sale securities $ $ $ $ Marketable securities had the following maturities as of December 31, 2016 (in thousands): Maturities Amount Year 2017 $ Thereafter As of December 31, 2016 and 2015, the Company had classified $409.9 million and $286.7 million of marketable securities, respectively, as short‑term since it had the intent to maintain a liquid portfolio and the ability to redeem the securities within one year. The Company has classified $2.3 million of investments as non‑current and has identified them as “Other assets” in the Company’s consolidated balance sheet as of December 31, 2015 (see Note 6).
Inventories	Inventories Inventories include expendable parts, fuel and supplies and are valued at cost (FIFO basis) less an allowance for obsolescence based on historical results, excess parts and management’s expectations of future operations. Expendable inventory parts are charged to expense as used. An obsolescence allowance for flight equipment expendable parts is accrued based on estimated lives of the corresponding fleet types and salvage values. The inventory allowance as of December 31, 2016 and 2015 was $40.5 million and $13.9 million, respectively. The significant increase in 2016 was related to additional excess inventory identified as part of the impairment analysis of the 50-seat aircraft. See Note 8, Special items, for additional detail on the impairment. These allowances are based on management estimates, which can be modified based on future changes in circumstances.
Property and Equipment	Property and Equipment Property and equipment are stated at cost and depreciated over their useful lives to their estimated residual values using the straight‑line method as follows: Assets Depreciable Life Residual Value New Aircraft 18 years % Used Aircraft, rotable spares, and spare engines up to 18 years 0 - 30 % Ground equipment up to 10 years % Office equipment up to 7 years % Leasehold improvements Shorter of 15 years or lease term % Buildings 20 – 39.5 years %
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets As of December 31, 2016, the Company had approximately $3.8 billion of property and equipment and related assets. Additionally, as of December 31, 2016, the Company had approximately $8.2 million in intangible assets. In accounting for these long‑lived and intangible assets, the Company makes estimates about the expected useful lives of the assets, the expected residual values of certain of these assets, and the potential for impairment based on the fair value of the assets and the cash flows they generate. On September 7, 2005, the Company acquired all of the issued and outstanding capital stock of Atlantic Southeast and recorded an intangible asset for specifically identifiable contracts of approximately $33.7 million relating to the acquisition. The intangible asset is being amortized over fifteen years under the straight‑line method. As of December 31, 2016 and 2015, the Company had $25.5 million and $23.3 million in accumulated amortization expense, attributable to the acquisition, respectively. Factors indicating potential impairment include, but are not limited to, significant decreases in the market value of the long‑lived assets, a significant change in the condition of the long‑lived assets and operating cash flow losses associated with the use of the long‑lived assets. On a periodic basis, the Company evaluates whether impairment indicators are present. When considering whether or not impairment of long‑lived assets exists, the Company groups similar assets together at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets and liabilities and compare the undiscounted cash flows for each asset group to the net carrying amount of the assets supporting the asset group. Asset groupings are done at the fleet or contract level. In December 2016, the Company decided to remove CRJ200 aircraft from ExpressJet’s operation. In connection therewith, the Company plans to remove approximately 46 CRJ200 aircraft from its fleet during 2017. Additionally, in December 2016, the Company entered into a termination agreement covering Bombardier’s residual value guarantee (“RVG”) agreements on 76 CRJ200 aircraft owned by SkyWest Airlines and ExpressJet whereby it agreed to terminate Bombardier’s future RVG commitment in exchange for a cash payment and other consideration valued at $125 million. The agreement also eliminated the Company`s future requirement to return the aircraft to a mid-time maintenance condition and certain remarketing activities. This termination agreement allowed for the acceleration of the retirement of the CRJ 200 fleet. As a result of the scheduled reduction in the CRJ200 fleet in 2017, the termination of the RVG agreements with Bombardier and the current market values of its CRJ200 aircraft excluding Bombardier’s RVGs, the Company concluded that indicators of impairment existed and therefore, evaluated its CRJ200 fleet and related assets for impairment. Pursuant to Accounting Standards Codification (“ASC”) 360-10, Impairment and Disposal of Long-Lived Assets, the Company determined that separate asset groups existed based on the various major partner contracts. A recoverability test was performed utilizing estimated undiscounted future cash flows for each asset group pursuant to applicable contracts with the major partners and associated expenses as well as the value the Company would realize upon disposal of aircraft. This was compared to the carrying value of the related assets resulting in a cash flow deficiency indicating that an impairment existed. The impairment analysis required the Company to perform an assessment of the fair value of its long-lived assets related to the CRJ200 aircraft within the asset groups utilized in the recoverability test. The Company engaged a third party to assist in determining the fair value of certain of the long-lived assets, including the aircraft, spare engines and fixed asset spare parts inventory. These values were estimated based on listed market values or recent third-party market transactions for similar assets. Additionally, the Company estimated the fair value of certain long-lived prepaid lease assets using the net present value of estimated current CRJ200 lease rates. All fair values are considered to be Level 3 within the fair value hierarchy. The amounts the Company may ultimately realize from the disposal of its CRJ200 long-lived assets may vary from the December 31, 2016 fair value assessments. See Note 8, Special Items , for the impairment charges recorded during the year ended December 31, 2016 related to the CRJ200 long-lived assets. Additionally, the Company’s fixed-fee contract with United covering Embraer ERJ145 regional jet aircraft ("ERJ145") is scheduled to expire at the end of 2017, subject to United’s two one-year extension rights intended to facilitate an orderly return of ERJ145 aircraft to United. The ERJ145 aircraft are leased from United and the Company is obligated to return the aircraft to United as each aircraft is scheduled to terminate under the contract. There are no significant unreimbursed return related costs associated with these lease returns. Under the terms of the fixed-fee contract, the Company anticipates removing approximately 45 ERJ145s from its fleet in 2017 and returning the aircraft to United. Due to the uncertainty regarding the probability of extending the ERJ145 fixed-fee arrangement with United beyond the existing terms and as the Company is obligated to return these aircraft to United upon the contract expiration, the Company also evaluated its ERJ145 related assets for impairment including spare engines and related spare parts inventory. The Company engaged a third party to assist in determining the fair value of the spare parts engines and inventory. The spare engines and inventory were valued based on recent market transactions for similar assets. All fair values are considered to be Level 3 within the fair value hierarchy. The amounts the Company may ultimately realize from the disposal of its ERJ145 long-lived assets may vary from the December 31, 2016 fair value assessments. See Note 8, Special Items , for the impairment charges recorded during the year ended December 31, 2016 related to the ERJ145 long-lived assets. The Company did not recognize any impairment charges of long-lived assets during 2015. In 2014, the Company had impairments on several long-lived assets relating to Embraer Brasilia EMB 120 (“EMB120”) turboprop aircraft, ERJ145 aircraft type specific assets and an aircraft paint facility located in Saltillo, Mexico. See Note 8, Special Items , for the impairment charges recorded during the year ended December 31, 2014 related to these long-lived assets.
Capitalized Interest	Capitalized Interest Interest is capitalized on aircraft purchase deposits as a portion of the cost of the asset and is depreciated over the estimated useful life of the asset. During the years ended December 31, 2016, 2015 and 2014, the Company capitalized interest costs of approximately $1.5 million, $2.2 million, and $1.8 million, respectively.
Maintenance	Maintenance The Company operates under a U.S. Federal Aviation Administration approved continuous inspection and maintenance program. The Company uses the direct expense method of accounting for its regional jet engine overhauls wherein the expense is recorded when the overhaul event occurs. The Company has engine services agreements with third-party vendors to provide long-term engine services covering the scheduled and unscheduled repairs for certain of its Bombardier CRJ700 Regional Jets (“CRJ700s”), Embraer ERJ145 regional jet aircraft and Embraer E175 jet (“E175”) aircraft. Under the terms of the agreements, the Company pays a fixed dollar amount per engine hour flown on a monthly basis and the third-party vendors will assume the responsibility to repair the engines at no additional cost to the Company, subject to certain specified exclusions. Maintenance costs under these contracts are recognized when the engine hour is flown pursuant to the terms of each contract. The costs of maintenance for airframe and avionics components, landing gear and normal recurring maintenance are expensed as incurred.
Passenger and Ground Handling Revenues	Passenger and Ground Handling Revenues The Company recognizes passenger and ground handling revenues when the service is provided under its code-share agreements. Under the Company’s fixed-fee arrangements (referred to as “fixed-fee arrangements, “fixed-fee contracts” or “capacity purchase agreements”) with Delta, United, American and Alaska (each, a “major airline partner”), the major airline partner generally pays the Company a fixed-fee for each departure, flight or block time incurred, and an amount per aircraft in service each month with additional incentives based on flight completion and on time performance. The major airline partner also directly reimburses the Company for certain direct expenses incurred under the fixed-fee arrangement such as fuel expense and landing fee expenses. Under the fixed-fee arrangements, revenue is earned when each flight is completed. Under the Company’s fixed-fee agreements with Delta, United, American and Alaska, the compensation structure generally consists of a combination of agreed‑upon rates for operating flights and direct reimbursement for other certain costs associated with operating the aircraft. A portion of the Company’s contract flying compensation is designed to reimburse the Company for certain aircraft ownership costs. The aircraft compensation structure varies by agreement, but is intended to cover either the Company’s aircraft principal and interest debt service costs, its aircraft depreciation and interest expense or its aircraft lease expense costs while the aircraft is under contract. Under the Company’s ExpressJet United Express ERJ Agreement and ExpressJet American ERJ145 Agreement, the major airline partner provides the aircraft to the Company for a nominal amount. The Company has concluded that a component of its revenue under these agreements is rental income, inasmuch as the agreements identify the “right of use” of a specific type and number of aircraft over a stated period of time. The amounts deemed to be rental income under the agreements for the years ended December 31, 2016, 2015 and 2014 were $516.0 million, $504.9 million and $497.0 million, respectively. These amounts are reflected as passenger revenues on the Company’s consolidated statements of comprehensive income (loss). The Company has not separately stated aircraft rental income and aircraft rental expense in the consolidated statement of comprehensive income (loss) since the use of the aircraft is not a separate activity of the total service provided. In the event that the contractual rates under the agreements have not been finalized at quarterly or annual financial statement dates, the Company records revenues based on the lower of prior period’s approved rates, as adjusted to reflect any contract negotiations and the Company’s estimate of rates that will be implemented in accordance with revenue recognition guidelines. In the event the Company has a reimbursement dispute with a major airline partner, the Company evaluates the dispute under its established revenue recognition criteria and, provided the revenue recognition criteria have been met, the Company recognizes revenue based on management’s estimate of the resolution of the dispute. In several of the Company’s agreements, the Company is eligible for incentive compensation upon the achievement of certain performance criteria. The incentives are defined in the agreements and are being measured and determined on a monthly, quarterly or semi-annual basis. At the end of each period, the Company calculates the incentives achieved during that period and recognizes revenue accordingly. The Company’s passenger and ground handling revenues could be impacted by a number of factors, including changes to the Company’s code‑share agreements with Delta, United, Alaska or American, contract modifications resulting from contract re‑negotiations, the Company’s ability to earn incentive payments contemplated under the Company’s code‑share agreements and settlement of reimbursement disputes with the Company’s major airline partners. Under a Revenue Sharing Arrangement (referred to as a “revenue-sharing” or “prorate” arrangement), the major airline and regional airline negotiate a passenger fare proration formula, pursuant to which the regional airline receives a percentage of the ticket revenues for those passengers traveling for one portion of their trip on the regional airline and the other portion of their trip on the major airline. Revenue is recognized under the Company’s prorate flying agreements when each flight is completed based upon the portion of the prorate passenger fare the Company anticipates that it will receive for each completed flight. Other ancillary revenues commonly associated with airlines such as baggage fee revenue, ticket change fee revenue and the marketing component of the sale of mileage credits are retained by the Company’s major airline partners on flights that the Company operates under its code-share agreements. The following summarizes the significant provisions of each code-share agreement the Company has with each major airline partner: Delta Connection Agreements Agreement Aircraft type Number of Aircraft Term / Termination SkyWest Airlines Delta Connection Agreement (fixed-fee arrangement)  CRJ 200  CRJ 700  CRJ 900  E175 50 27 36 13  Individual aircraft have scheduled removal dates under the agreement between 2017 and 2026  The average remaining term of the aircraft under contract is 3.7 years ExpressJet Delta Connection Agreement (fixed-fee arrangement)  CRJ 200  CRJ 700  CRJ 900 38 35 28  Individual aircraft have scheduled removal dates under the agreement between 2017 and 2022  The average remaining term of the aircraft under contract is 2.8 years SkyWest Airlines Delta Connection Prorate Agreement (revenue-sharing arrangement)  CRJ 200 21  Terminable with 30-day notice United Express Agreements Agreement Aircraft type Number of Aircraft Term / Termination SkyWest Airlines United Express Agreements (fixed-fee arrangement)  CRJ 200  CRJ 700  E175 53 35 58  Individual aircraft have scheduled removal dates under the agreement between 2017 and 2027  The average remaining term of the aircraft under contract is 5.7 years ExpressJet United ERJ Agreement (fixed-fee arrangement)  ERJ 145  ERJ 135 140 5  Individual aircraft have scheduled removal dates under the agreement during 2017, subject to two one-year extensions   The average remaining term of the aircraft under contract is 0.9 years SkyWest Airlines United Express Prorate Agreement (revenue-sharing arrangement)  CRJ 200 22  Terminable with 120-day notice American Agreements Agreement Aircraft type Number of Aircraft Term / Termination Dates SkyWest Airlines American Agreement (fixed-fee arrangement)  CRJ 200  CRJ 700 9 23  CRJ200 aircraft are scheduled to expire in 2017 and the CRJ700 aircraft are scheduled to expire in 2019 SkyWest Airlines American Prorate Agreement (revenue-sharing arrangement)  CRJ 200 6  Terminable with 120-day notice ExpressJet American Agreement (fixed-fee arrangement)  CRJ 200  CRJ 700  ERJ 145 11 10 14  CRJ200 aircraft are scheduled to expire in 2017 and the CRJ700 aircraft are scheduled to expire in 2020 ExpressJet American Prorate Agreement (revenue-sharing arrangement)  CRJ 200 3  Terminable with 120-day notice Alaska Capacity Purchase Agreement Agreement Aircraft type Number of Aircraft Term / Termination SkyWest Airlines Alaska Agreement (fixed-fee arrangement)  E175 15  Individual aircraft have scheduled removal dates under the agreement between 2027 and 2028 The Company anticipates placing an additional seven E175 aircraft with United, five additional E175 aircraft with Alaska and six E175 aircraft with Delta throughout 2017. The Company is scheduled to have 49 CRJ700 aircraft in service with American by mid-2017, all of which were previously operated in the existing fleet of other major airline partners. At the end of 2016, the Company had 213 CRJ200 aircraft and 159 ERJ145/135 aircraft in scheduled service. The Company anticipates it will reduce its CRJ200 aircraft by approximately 46 aircraft and its ERJ145/135 aircraft by approximately 59 aircraft during 2017. The Company also anticipates that ExpressJet will transition to flying primarily dual-class aircraft in its CRJ aircraft operation by removing its CRJ200 aircraft from service over the next year.
Deferred Aircraft Credits	The Company is scheduled to have 49 CRJ700 aircraft in service with American by mid-2017, all of which were previously operated in the existing fleet of other major airline partners. At the end of 2016, the Company had 213 CRJ200 aircraft and 159 ERJ145/135 aircraft in scheduled service. The Company anticipates it will reduce its CRJ200 aircraft by approximately 46 aircraft and its ERJ145/135 aircraft by approximately 59 aircraft during 2017. The Company also anticipates that ExpressJet will transition to flying primarily dual-class aircraft in its CRJ aircraft operation by removing its CRJ200 aircraft from service over the next year. Deferred Aircraft Credits The Company accounts for incentives provided by aircraft manufacturers as deferred credits. The deferred credits related to leased aircraft are amortized on a straight‑line basis as a reduction to rent expense over the lease term. Credits related to owned aircraft reduce the purchase price of the aircraft, which has the effect of amortizing the credits on a straight‑line basis as a reduction in depreciation expense over the life of the related aircraft. The incentives are credits that may be used to purchase spare parts and pay for training and other expenses.
Income Taxes	Income Taxes The Company recognizes a liability or asset for the deferred tax consequences of all temporary differences between the tax basis of assets and liabilities and their reported amounts in the consolidated financial statements that are expected to result in taxable or deductible amounts in future years when the reported amounts of the assets and liabilities are recovered or settled.
Net Income (Loss) Per Common Share	Net Income (Loss) Per Common Share Basic net income (loss) per common share (“Basic EPS”) excludes dilution and is computed by dividing net income (loss) by the weighted average number of common shares outstanding during the period. Diluted net income (loss) per common share (“Diluted EPS”) reflects the potential dilution that could occur if stock options or other contracts to issue common stock were exercised or converted into common stock. The computation of Diluted EPS does not assume exercise or conversion of securities that would have an anti‑dilutive effect on net income (loss) per common share. During the years ended December 31, 2016, 2015 and 2014, 2,077,000, 505,000 and 3,191,000 shares reserved for issuance upon the exercise of outstanding options were excluded from the computation of Diluted EPS respectively, as the respective exercise price exceeded the weighted average fair market value of the Company’s stock for such year. The calculation of the weighted average number of common shares outstanding for Basic EPS and Diluted EPS are as follows for the years ended December 31, 2016, 2015 and 2014 (in thousands): Year Ended December 31, 2016 2015 2014 Numerator: Net Income (Loss) $ $ $ Denominator: Denominator for basic earnings per-share weighted average shares Dilution due to stock options and restricted stock units — — Denominator for diluted earnings per-share weighted average shares Basic earnings (loss) per-share $ $ $ Diluted earnings (loss) per-share $ $ $
Comprehensive Income (Loss)	Comprehensive Income (Loss) Comprehensive income (loss) includes charges and credits to stockholders’ equity that are not the result of transactions with the Company’s shareholders, including changes in unrealized appreciation (depreciation) on marketable securities. Comprehensive loss for the year ended December 31, 2014 included unrealized gain (loss) on foreign currency translation adjustment related to the Company’s equity investment in Trip Linhas Aéreas, a regional airline operating in Brazil (“TRIP”).
Fair Value of Financial Instruments	Fair Value of Financial Instruments The carrying amounts reported in the consolidated balance sheets for receivables and accounts payable approximate fair values because of the immediate or short‑term maturity of these financial instruments. Marketable securities are reported at fair value based on market quoted prices in the consolidated balance sheets. If quoted prices in active markets are no longer available, the Company has estimated the fair values of these securities utilizing a discounted cash flow analysis as of December 31, 2016. These analyses consider, among other items, the collateralization underlying the security investments, the creditworthiness of the counterparty, the timing of expected future cash flows, and the expectation of the next time the security is expected to have a successful auction. The fair value of the Company’s long‑term debt is estimated based on current rates offered to the Company for similar debt and was approximately $2,566.5 million as of December 31, 2016, as compared to the carrying amount of $2,570.9 million as of December 31, 2016. The Company’s fair value of long‑term debt as of December 31, 2015 was $1,939.8 million as compared to the carrying amount of $1,948.8 million as of December 31, 2015.
Segment Reporting	Segment Reporting Generally accepted accounting principles require disclosures related to components of a company for which separate financial information is available to, and regularly evaluated by, the Company’s chief operating decision maker when deciding how to allocate resources and in assessing performance. The Company’s three operating segments consist of the operations conducted by SkyWest Airlines, ExpressJet and SkyWest Leasing. Information pertaining to the Company’s reportable segments is presented in Note 2, Segment Reporting .
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update No. 2014-09, “Revenue from Contracts with Customers” (“ASU No. 2014-09”). Under ASU No. 2014-09, revenue is recognized at the time a good or service is transferred to a customer for the amount of consideration received for that specific good or service. In July 2015, the FASB deferred the effective date of ASU No. 2014-09 for annual reporting periods beginning after December 15, 2017. In 2016, the FASB issued several amendments to the standard, including principal versus agent considerations when another party is involved in providing goods or services to a customer and the application of identifying performance obligations. The Company continues to assess the potential impacts of ASU No. 2014-09 on its fixed-fee contracts, prorate flying agreements, ground handling agreements and other revenue transactions. The Company anticipates completing its review of the impact by the second quarter of 2017. Interpretations are on-going and could have a significant impact on the Company’s implementation. The Company believes the principal versus agent considerations may change how the Company presents revenue for certain directly-reimbursed expenses under its fixed-fee contracts, such as fuel expenses. ASU No. 2014-09 is required to be applied either full retrospective to each prior reporting period presented or modified retrospective with the cumulative effect of initially applying it at the date of initial application. The Company anticipates using the full retrospective method of adoption. In April 2015, the FASB issued Account Standards Update No. 2015-03, “Interest—Imputation of Interest: Simplifying the Presentation of Debt Issuance Costs,” which requires debt issuance costs related to a recognized debt liability to be presented as a direct deduction from the carrying amount of that debt liability. The new guidance only impacts financial statement presentation. The guidance was effective in the first quarter of 2016. The Company adopted this guidance January 1, 2016 on a retrospective basis. As a result, $20.9 million of unamortized debt issuance costs that had been included in the Other assets line on the consolidated balance sheets as of December 31, 2015 are now presented as direct deductions from the carrying amounts of the related debt liabilities. In November 2015, the FASB issued Accounting Standards Update 2015-17, “Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes” (“ASU No. 2015-17”). ASU No. 2015-17 requires that deferred tax liabilities and assets be classified as noncurrent in a classified statement of financial position. The current requirement that deferred tax liabilities and assets of a tax-paying component of an entity be offset and presented as a single amount is not affected by ASU No. 2015-17. ASU No. 2015-17 is effective for annual periods beginning after December 15, 2016, and interim periods within those annual periods. The Company’s management currently anticipates the impact of adopting ASU No. 2015-17 to result in reducing the Company’s current deferred tax asset to zero with corresponding resolution in the recorded amount of the Company’s long-term deferred tax liabilities. In February 2016, the FASB issued Accounting Standards Update 2016-02, “Leases (Topic 842)” (“ASU No. 2016-02”). ASU No. 2016-02 amends the existing accounting standards for lease accounting, including requiring lessees to recognize most leases on their balance sheets and making targeted changes to lessor accounting. ASU No. 2016-02 will be effective beginning in the first quarter of 2019. Early adoption of ASU No. 2016-02 is permitted. ASU No. 2016-02 requires a modified retrospective transition approach for all leases existing at, or entered into after, the date of initial application, with an option to use certain transition relief. The Company’s management is currently evaluating the impact the adoption of ASU 2016-02 is anticipated to have on the Company’s consolidated financial statements. In March 2016, the FASB issued Accounting Standards Update No. 2016-09, “Compensation—Stock Compensation (Topic 718)” (“ASU No. 2016-09”). ASU No. 2016-09 makes several modifications to Topic 718 related to the accounting for forfeitures, employer tax withholding on share-based compensation and the financial statement presentation of excess tax benefits or deficiencies. ASU No. 2016-09 also clarifies the statement of cash flows presentation for certain components of share-based awards. ASU No. 2016-09 is effective for interim and annual reporting periods beginning after December 15, 2016, although early adoption is permitted. The Company’s management anticipates the adoption of ASU No. 2016-09 will likely impact the Company’s income tax provision, shareholders' equity and statement of cash flows consolidated financial statements. The impact is anticipated to vary depending on the employee stock option exercises each year.

Nature of Operations and Summ23

Nature of Operations and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2016
Nature of operations and significant accounting policies summary
Schedule of details of aircraft and agreements with other airlines	As of December 31, 2016, the Company had 652 aircraft in scheduled service out of a combined fleet of 685 aircraft consisting of the following: CRJ200 CRJ700 CRJ900 ERJ135 ERJ145 E175 EMB120 Total United — — Delta — — — American — — — — Alaska — — — — — — Aircraft in scheduled service — Subleased to an un-affiliated entity — — — — — — Other* — — — Total Fleet *Other aircraft consisted of leased aircraft removed from service that were in the process of being returned to the lessor and owned aircraft removed from service that are in the process of being sold.
Schedule of the Company's position in marketable securities	The Company’s position in marketable securities as of December 31, 2016 and 2015 was as follows (in thousands): Gross unrealized Gross unrealized At December 31, 2016 Amortized Cost holding gains holding losses Fair market value Total cash and cash equivalents $ $ — $ — $ Available-for-sale securities: Bond and bond funds $ $ — $ $ Asset backed securities — — Total available-for-sale securities $ $ — $ $ Total cash and cash equivalents and available for sale securities $ $ — $ $ Gross unrealized Gross unrealized At December 31, 2015 Amortized Cost holding gains holding losses Fair market value Total cash and cash equivalents $ $ — $ — $ Available-for-sale securities: Bond and bond funds $ $ — $ $ Asset backed securities — Total available-for-sale securities $ $ $ $ Total cash and cash equivalents and available for sale securities $ $ $ $
Schedule of maturities of marketable securities	Marketable securities had the following maturities as of December 31, 2016 (in thousands): Maturities Amount Year 2017 $ Thereafter
Schedule of property and equipment	Assets Depreciable Life Residual Value New Aircraft 18 years % Used Aircraft, rotable spares, and spare engines up to 18 years 0 - 30 % Ground equipment up to 10 years % Office equipment up to 7 years % Leasehold improvements Shorter of 15 years or lease term % Buildings 20 – 39.5 years %
Net income with per share data and comprehensive income
Schedule of net income (loss) per common share	Year Ended December 31, 2016 2015 2014 Numerator: Net Income (Loss) $ $ $ Denominator: Denominator for basic earnings per-share weighted average shares Dilution due to stock options and restricted stock units — — Denominator for diluted earnings per-share weighted average shares Basic earnings (loss) per-share $ $ $ Diluted earnings (loss) per-share $ $ $
Delta Connection Agreements
Nature of operations and significant accounting policies summary
Schedule of details of aircraft and agreements with other airlines	Agreement Aircraft type Number of Aircraft Term / Termination SkyWest Airlines Delta Connection Agreement (fixed-fee arrangement)  CRJ 200  CRJ 700  CRJ 900  E175 50 27 36 13  Individual aircraft have scheduled removal dates under the agreement between 2017 and 2026  The average remaining term of the aircraft under contract is 3.7 years ExpressJet Delta Connection Agreement (fixed-fee arrangement)  CRJ 200  CRJ 700  CRJ 900 38 35 28  Individual aircraft have scheduled removal dates under the agreement between 2017 and 2022  The average remaining term of the aircraft under contract is 2.8 years SkyWest Airlines Delta Connection Prorate Agreement (revenue-sharing arrangement)  CRJ 200 21  Terminable with 30-day notice
United Express Agreements
Nature of operations and significant accounting policies summary
Schedule of details of aircraft and agreements with other airlines	Agreement Aircraft type Number of Aircraft Term / Termination SkyWest Airlines United Express Agreements (fixed-fee arrangement)  CRJ 200  CRJ 700  E175 53 35 58  Individual aircraft have scheduled removal dates under the agreement between 2017 and 2027  The average remaining term of the aircraft under contract is 5.7 years ExpressJet United ERJ Agreement (fixed-fee arrangement)  ERJ 145  ERJ 135 140 5  Individual aircraft have scheduled removal dates under the agreement during 2017, subject to two one-year extensions   The average remaining term of the aircraft under contract is 0.9 years SkyWest Airlines United Express Prorate Agreement (revenue-sharing arrangement)  CRJ 200 22  Terminable with 120-day notice
American Agreements
Nature of operations and significant accounting policies summary
Schedule of details of aircraft and agreements with other airlines	Agreement Aircraft type Number of Aircraft Term / Termination Dates SkyWest Airlines American Agreement (fixed-fee arrangement)  CRJ 200  CRJ 700 9 23  CRJ200 aircraft are scheduled to expire in 2017 and the CRJ700 aircraft are scheduled to expire in 2019 SkyWest Airlines American Prorate Agreement (revenue-sharing arrangement)  CRJ 200 6  Terminable with 120-day notice ExpressJet American Agreement (fixed-fee arrangement)  CRJ 200  CRJ 700  ERJ 145 11 10 14  CRJ200 aircraft are scheduled to expire in 2017 and the CRJ700 aircraft are scheduled to expire in 2020 ExpressJet American Prorate Agreement (revenue-sharing arrangement)  CRJ 200 3  Terminable with 120-day notice
Alaska Capacity Purchase Agreement
Nature of operations and significant accounting policies summary
Schedule of details of aircraft and agreements with other airlines	Agreement Aircraft type Number of Aircraft Term / Termination SkyWest Airlines Alaska Agreement (fixed-fee arrangement)  E175 15  Individual aircraft have scheduled removal dates under the agreement between 2027 and 2028

Segment Reporting (Tables)

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting
Schedule of Company's segment data	The following represents the Company’s segment data for the years ended December 31, 2016, 2015 and 2014 (in thousands). Year Ended December 31, 2016 SkyWest Airlines ExpressJet SkyWest Leasing Consolidated Operating revenues $ $ $ $ Operating expense Depreciation and amortization expense Special items — Interest expense Segment profit (loss) (1) Identifiable intangible assets, other than goodwill — — Total assets Capital expenditures (including non-cash) Year Ended December 31, 2015 SkyWest Airlines ExpressJet SkyWest Leasing Consolidated Operating revenues $ $ $ $ Operating expense Depreciation and amortization expense Interest expense Segment profit (loss) (1) Identifiable intangible assets, other than goodwill — — Total assets Capital expenditures (including non-cash) Year Ended December 31, 2014 SkyWest Airlines ExpressJet SkyWest Leasing Consolidated Operating revenues $ $ $ $ Operating expense Depreciation and amortization expense Special items — Interest expense Segment profit (loss) (1) Identifiable intangible assets, other than goodwill — — Total assets Capital expenditures (including non-cash) Segment profit is operating income less interest expense

Long-Term Debt (Tables)

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2016
Long-Term Debt
Schedule of long-term debt	Long‑term debt consisted of the following as of December 31, 2016 and 2015 (in thousands): December 31, December 31, 2016 2015 Notes payable to banks, due in semi-annual installments, variable interest based on LIBOR, or with interest rates ranging from 2.64% to 2.82% through 2017 to 2020, secured by aircraft $ $ Notes payable to a financing company, due in semi-annual installments, variable interest based on LIBOR, or with interest rates ranging from 2.27% to 3.25% through 2017 to 2021, secured by aircraft Notes payable to banks, due in semi-annual installments plus interest at 6.06% to 6.51% through 2021, secured by aircraft Notes payable to a financing company, due in semi-annual installments plus interest at 5.78% to 6.23% through 2017, secured by aircraft Notes payable to banks, due in monthly installments plus interest of 2.68% to 6.86% through 2025, secured by aircraft Notes payable to banks, due in monthly installments, plus interest at 6.05% through 2020, secured by aircraft Notes payable to banks, due in monthly installments, plus interest at 3.44% through 2019, secured by aircraft Notes payable to banks, due in quarterly installments plus interest at 3.39% to 4.68% through 2028, secured by aircraft Notes payable to banks, due in monthly installments, plus interest based on LIBOR at 3.54% through 2017, secured by aircraft Notes payable to banks due in monthly installments, interest at 3.30% through 2019, secured by spare engines Long-term debt $ $ Less current maturities Long-term debt, net of current maturities $ $
Schedule of adopted guidance ASU 2015-03	The Company adopted guidance ASU 2015-03 on January 1, 2016. As a result, the unamortized debt issuance costs that had been included in Other assets line on the consolidated balance sheets as of December 31, 2015 are now presented as direct deductions from the carrying amounts of the related debt liabilities as shown below as of December 31, 2016 and 2015 (see Note 1 Nature of Operations and Summary of Significant Accounting Policies ) (in thousands): December 31, 2016 December 31, 2015 Current portion long-term debt $ $ Long-term debt net of current maturities Total long-term debt (including current portion) $ $ Unamortized debt issue cost, net Total long-term debt, net of debt issue costs $ $
Schedule of maturities of long-term debt	The aggregate amounts of principal maturities of long‑term debt as of December 31, 2016 were as follows (in thousands): 2017 $ 2018 2019 2020 2021 Thereafter $

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Taxes
Schedule of components of provision for income taxes	The provision for income taxes includes the following components (in thousands): Year ended December 31, 2016 2015 2014 Current tax provision (benefit): Federal $ $ $ State Foreign — Deferred tax provision (benefit): Federal State Provision for income taxes $ $ $
Schedule of income tax rate reconciliation	Year ended December 31, 2016 2015 2014 Current tax provision (benefit): Federal $ $ $ State Foreign — Deferred tax provision (benefit): Federal State Provision for income taxes $ $ $ The following is a reconciliation between the statutory federal income tax rate of 35% and the effective rate which is derived by dividing the provision for income taxes by income (loss) before for income taxes (in thousands): Year ended December 31, 2016 2015 2014 Computed provision (benefit) for income taxes at the statutory rate $ $ $ Increase (decrease) in income taxes resulting from: State income tax provision (benefit), net of federal income tax benefit Non-deductible expenses Valuation allowance changes affecting the provision for income taxes Foreign income taxes, net of federal & state benefit — — Other, net Provision for income taxes $ $ $
Schedule of components of the net deferred tax assets and liabilities	The significant components of the Company’s net deferred tax assets and liabilities as of December 31, 2015 and 2014 are as follows (in thousands): As of December 31, 2016 2015 Deferred tax assets: Intangible asset $ $ Accrued benefits Net operating loss carryforward AMT credit carryforward Deferred aircraft credits Accrued reserves and other Total deferred tax assets Valuation allowance Deferred tax liabilities: Accelerated depreciation Total deferred tax liabilities Net deferred tax liability $ $

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies
Schedule of Future Minimum Rental Payments for Operating Leases	The following table summarizes future minimum rental payments required under operating leases that have non‑cancelable lease terms as of December 31, 2016 (in thousands): 2017 $ 2018 2019 2020 2021 Thereafter $
Schedule of Employees Under Collective Bargaining Agreements	Approximate Number of Active Employees Status of Employee Group Represented Representatives Agreement Atlantic Southeast Pilots Air Line Pilots Association International Amendable February 2018 Atlantic Southeast Flight Attendants International Association of Machinists and Aerospace Workers Currently Amendable Atlantic Southeast Flight Controllers Transport Workers Union of America Currently Amendable Atlantic Southeast Mechanics International Brotherhood of Teamsters Currently Amendable Atlantic Southeast Stock Clerks International Brotherhood of Teamsters Currently Amendable ExpressJet Delaware Pilots Air Line Pilots Association International Amendable February 2018 ExpressJet Delaware Flight Attendants International Association of Machinists and Aerospace Workers Currently Amendable ExpressJet Delaware Mechanics International Brotherhood of Teamsters Currently Amendable ExpressJet Delaware Dispatchers Transport Workers Union of America Currently Amendable ExpressJet Delaware Stock Clerks International Brotherhood of Teamsters Currently Amendable

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value Measurements
Schedule of assets measured at fair value on a recurring basis	As of December 31, 2016, the Company held certain assets that are required to be measured at fair value on a recurring basis. Assets measured at fair value on a recurring basis are summarized below (in thousands): Fair Value Measurements as of December 31, 2016 Total Level 1 Level 2 Level 3 Marketable Securities Bonds and bond funds $ $ — $ $ — Commercial paper — — Asset backed securities $ $ — $ $ — Cash, Cash Equivalents and Restricted Cash — — Total Assets Measured at Fair Value $ $ $ $ — Fair Value Measurements as of December 31, 2015 Total Level 1 Level 2 Level 3 Marketable Securities Bonds and bond funds $ $ — $ $ — Commercial paper — — Asset backed securities $ $ — $ $ — Cash, Cash Equivalents and Restricted Cash — — Auction Rate Securities(a) — — Total Assets Measured at Fair Value $ $ $ $ (a) Auction rate securities included in long-term “Other assets” in the Consolidated Balance Sheet
Schedule of fair value measurements using significant unobservable inputs	The following table presents the Company’s assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3) at December 31, 2016 (in thousands): Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Auction Rate Securities Balance at January 1, 2016 $ Total realized and unrealized gains or (losses) Included in earnings Included in other comprehensive income Transferred out — Settlements Balance at December 31, 2016 $ —

Special Items (Tables)

Special Items (Tables)	12 Months Ended
	Dec. 31, 2016
Special Items
Summary of the components of special items	The following table summarizes the components of the Company's special items, for the year ended December 31, 2016, 2015 and 2014 (in thousands): Year ended December 31, 2016 2015 2014 Special items: CRJ200 aircraft related items 1 $ $ — $ — EMB120 aircraft related items 2 — — ERJ145 aircraft related items 3 — Paint facility and related items 4 — — Total special items $ $ — $ (1) Consists primarily of inventory valuation charges and impairment charges to write-down CRJ200 aircraft including related long-lived assets to their estimated fair value. The estimated fair value of the long-lived assets, including the aircraft and fixed asset spare parts inventory, was based on third party appraisals on the assets. These values were estimated based on listed market values or recent third-party market transactions for similar assets. Additionally, the Company estimated the fair value of certain long-lived prepaid lease assets using the net present value of estimated current CRJ200 lease rates. All fair values are considered to be Level 3 within the fair value hierarchy. Of the special items $184.3 million related to SkyWest Airlines and $240.2 million related to ExpressJet. These charges are net of $90 million in cash proceeds and other considerations from the Bombardier termination agreement. These special items are reflected in the SkyWest Airlines and ExpressJet operating expenses under Note 2 Segment Reporting. (2) Consists primarily of impairment charges to write-down owned EMB120 aircraft including capitalized engine overhaul costs, and related long-lived assets to their estimated fair value and accrued obligations on leased aircraft and related costs. The estimated fair value of the long-lived assets was based on third party valuations for similar assets which is considered an unobservable input (Level 3) under the fair value hierarchy. In November 2014, the Company approved a plan to discontinue operating the EMB120 aircraft by the end of the second quarter of 2015. The decision to discontinue use of the EMB120 aircraft included management’s assessment of the need for pilots to operate upcoming deliveries for the E175 aircraft, the incremental training cost to hire new pilots compared to retraining existing EMB120 pilots to operate CRJ or E175 aircraft, and the uncertainty related to the number of qualified pilots available for hire, combined with the overall age and increased operating costs of the Company’s EMB120 fleet. These special items are reflected in the SkyWest Airlines operating expenses under Note 2 Segment Reporting. (3) The ERJ145 aircraft related items recorded in the 2016 special charge consist primarily of inventory valuation charges and impairment charges to write-down certain ERJ145 long-lived assets, which primarily consisted of spare engines and ERJ145 spare aircraft parts, to their estimated fair value of $41.2 million. The estimated fair value of the long-lived assets was based on third party appraisals and valuations for similar assets which is considered an unobservable input (Level 3) under the fair value hierarchy. These special items are reflected in the ExpressJet operating expenses under Note 2 Segment Reporting . The ERJ145 aircraft related items recorded in the 2014 special charge consist primarily of impairment charges to write-down certain ERJ145 long-lived assets, which primarily consisted of spare engines and ERJ145 spare aircraft parts, to their estimated fair value of $11.4 million and accrued obligations on leased aircraft and related costs of $1.5 million. The estimated fair value of the long-lived assets was based on third party valuations for similar assets which is considered an unobservable input (Level 3) under the fair value hierarchy. These special items are reflected in the ExpressJet operating expenses under Note 2 Segment Reporting . Consists primarily of the write-down of assets associated with the disposition of the Company’s paint facility located in Saltillo, Mexico, which was sold during the year ended December 31, 2014. These special items are reflected in the ExpressJet operating expenses under Note 2 Segment Reporting .

Capital Transactions (Tables)

Capital Transactions (Tables)	12 Months Ended
	Dec. 31, 2016
Schedule of assumptions used and weighted average fair value for stock option grants	2016 2015 2014 Expected annual dividend rate % % % Risk-free interest rate % % % Average expected life (years) Expected volatility of common stock Forfeiture rate % % % Weighted average fair value of option grants $ $ $
Schedule of restricted stock activity	During the year ended December 31, 2016, the Company granted 380,358 shares of restricted stock units to certain Company’s employees under the 2010 Incentive Plan. The restricted stock units granted during the year ended December 31, 2016 have a three‑year vesting period, during which the recipient must remain employed with the Company or its subsidiaries. The weighted average fair value of the restricted stock units the date of grants made during the year ended December 31, 2016 was $14.81 per share. The following table summarizes the activity of restricted stock units granted to certain Company employees as of December 31, 2016, 2015 and 2014: Weighted-Average Grant-Date Fair Number of Shares Value Non-vested shares outstanding at December 31, 2013 $ Granted Vested Cancelled Non-vested shares outstanding at December 31, 2014 Granted Vested Cancelled Non-vested shares outstanding at December 31, 2015 Granted Vested Cancelled Non-vested shares outstanding at December 31, 2016 $
Schedule of stock option activity	2016 2015 2014 Weighted Weighted Average Aggregate Weighted Weighted Average Remaining Intrinsic Average Average Number of Exercise Contractual Value Number of Exercise Number of Exercise Options Price Term ($000) Options Price Options Price Outstanding at beginning of year $ years $ $ $ Granted Exercised Cancelled Outstanding at end of year years $ Exercisable at December 31, 2016 years $ Exercisable at December 31, 2015 years $
Schedule of non-vested stock options	The following table summarizes the status of the Company’s non‑vested stock options as of December 31, 2016: Weighted-Average Number of Grant-Date Shares Fair Value Non-vested shares at beginning of year $ Granted Vested Cancelled Non-vested shares at end of year $
Schedule of stock options outstanding	The following table summarizes information about the Company’s stock options outstanding at December 31, 2016: Options Outstanding Options Exercisable Weighted Average Number Remaining Weighted Average Number Weighted Average Range of Exercise Prices Outstanding Contractual Life Exercise Price Exercisable Exercise Price $8 to $11 years $ — $ — $12 to $14 years $15 to $19 years $8 to $19 years $ $
Performance share units
Schedule of non-vested stock options	The following table summarizes the activity of performance share units granted at target as of December 31, 2016. Weighted-Average Grant-Date Fair Number of Shares Value Non-vested shares outstanding at December 31, 2014 — $ — Granted Vested — — Cancelled Non-vested shares outstanding at December 31, 2015 $ Granted Vested — — Cancelled Non-vested shares outstanding at December 31, 2016 $

Retirement Plans and Employee31

Retirement Plans and Employee Stock Purchase Plans (Tables)	12 Months Ended
	Dec. 31, 2016
Retirement Plans and Employee Stock Purchase Plans
Schedule of purchases made under the 2009 Employee Stock Purchase Plans	Year ended December 31, 2016 2015 2014 Number of shares purchased Average price of shares purchased $ $ $

Quarterly Financial Data (Una32

Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Data (Unaudited)
Schedule of Quarterly Financial Data (Unaudited)	Unaudited summarized financial data by quarter for 2016 and 2015 is as follows (in thousands, except per share data): Year ended December 31, 2016 First Second Third Fourth Quarter Quarter Quarter Quarter Year Operating revenues $ $ $ $ $ Operating income Net income (loss)(1) Net income (loss) per common share: Basic Diluted Weighted average common shares: Basic: Diluted: Year ended December 31, 2015 First Second Third Fourth Quarter Quarter Quarter Quarter Year Operating revenues $ $ $ $ $ Operating income Net income Net income per common share: Basic Diluted Weighted average common shares: Basic: Diluted: Operating loss for the fourth quarter of 2016 included a special charge of $465.6 million related to an impairment on the Company’s 50-seat aircraft.

Nature of Operations and Summ33

Nature of Operations and Summary of Significant Accounting Policies - Aircraft Fleet (Details)	12 Months Ended
	Dec. 31, 2016itemaircraft
Agreements with other airlines
Number of daily departures to different destinations | item	3,160
Number of aircraft held by entity	685
CRJ 200
Agreements with other airlines
Number of aircraft held by entity	215
CRJ 700
Agreements with other airlines
Number of aircraft held by entity	139
CRJ 900
Agreements with other airlines
Number of aircraft held by entity	64
ERJ 135
Agreements with other airlines
Number of aircraft held by entity	9
ERJ 145
Agreements with other airlines
Number of aircraft held by entity	158
E 175
Agreements with other airlines
Number of aircraft held by entity	86
EMB 120
Agreements with other airlines
Number of aircraft held by entity	14
United
Agreements with other airlines
Number of aircraft held by entity	313
Percentage of aggregate capacity operated	52.20%
United | CRJ 200
Agreements with other airlines
Number of aircraft held by entity	75
United | CRJ 700
Agreements with other airlines
Number of aircraft held by entity	35
United | ERJ 135
Agreements with other airlines
Number of aircraft held by entity	5
United | ERJ 145
Agreements with other airlines
Number of aircraft held by entity	140
United | E 175
Agreements with other airlines
Number of aircraft held by entity	58
Delta
Agreements with other airlines
Number of aircraft held by entity	248
Percentage of aggregate capacity operated	36.50%
Delta | CRJ 200
Agreements with other airlines
Number of aircraft held by entity	109
Delta | CRJ 700
Agreements with other airlines
Number of aircraft held by entity	62
Delta | CRJ 900
Agreements with other airlines
Number of aircraft held by entity	64
Delta | E 175
Agreements with other airlines
Number of aircraft held by entity	13
American
Agreements with other airlines
Number of aircraft held by entity	76
Percentage of aggregate capacity operated	6.30%
American | CRJ 200
Agreements with other airlines
Number of aircraft held by entity	29
American | CRJ 700
Agreements with other airlines
Number of aircraft held by entity	33
American | ERJ 145
Agreements with other airlines
Number of aircraft held by entity	14
Alaska
Agreements with other airlines
Number of aircraft held by entity	15
Percentage of aggregate capacity operated	5.00%
Alaska | E 175
Agreements with other airlines
Number of aircraft held by entity	15
Aircraft in scheduled service
Agreements with other airlines
Number of aircraft held by entity	652
Aircraft in scheduled service | CRJ 200
Agreements with other airlines
Number of aircraft held by entity	213
Aircraft in scheduled service | CRJ 700
Agreements with other airlines
Number of aircraft held by entity	130
Aircraft in scheduled service | CRJ 900
Agreements with other airlines
Number of aircraft held by entity	64
Aircraft in scheduled service | ERJ 135
Agreements with other airlines
Number of aircraft held by entity	5
Aircraft in scheduled service | ERJ 145
Agreements with other airlines
Number of aircraft held by entity	154
Aircraft in scheduled service | E 175
Agreements with other airlines
Number of aircraft held by entity	86
Subleased to an un-affiliated entity
Agreements with other airlines
Number of aircraft held by entity	2
Subleased to an un-affiliated entity | CRJ 200
Agreements with other airlines
Number of aircraft held by entity	2
Other
Agreements with other airlines
Number of aircraft held by entity	31
Other | CRJ 700
Agreements with other airlines
Number of aircraft held by entity	9
Other | ERJ 135
Agreements with other airlines
Number of aircraft held by entity	4
Other | ERJ 145
Agreements with other airlines
Number of aircraft held by entity	4
Other | EMB 120
Agreements with other airlines
Number of aircraft held by entity	14

Nature of Operations and Summ34

Nature of Operations and Summary of Significant Accounting Policies - Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Nature of Operations and Summary of Significant Accounting Policies
Restricted cash	$ 8,243	$ 8,216

Nature of Operations and Summ35

Nature of Operations and Summary of Significant Accounting Policies - Marketable Securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Marketable Securities
Total cash and cash equivalents	$ 146,766	$ 203,035	$ 132,275	$ 170,636
Amortized Cost	410,014	286,887
Gross unrealized holding gains		1
Gross unrealized holding losses	(116)	(220)
Marketable securities	409,898	286,668
Total cash and cash equivalents and available for sale securities, amortized cost	556,780	489,922
Total cash and cash equivalents and available for sale securities, fair market value	556,664	489,703
Maturities of marketable securities
Year 2,017	293,928
Thereafter	115,970
Marketable Securities
Marketable securities	$ 409,898	286,668
Maximum period for redemption	1 year
Investment classified as non-current		2,300
Bonds and bond funds
Marketable Securities
Amortized Cost	$ 410,001	286,857
Gross unrealized holding losses	(116)	(220)
Marketable securities	409,885	286,637
Asset-backed securities
Marketable Securities
Amortized Cost	13	30
Gross unrealized holding gains		1
Marketable securities	$ 13	$ 31

Nature of Operations and Summ36

Nature of Operations and Summary of Significant Accounting Policies - Inventories (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)item	Dec. 31, 2015USD ($)
Inventories
Inventory allowance | $	$ 40.5	$ 13.9
Number of seats on aircraft | item	50

Nature of Operations and Summ37

Nature of Operations and Summary of Significant Accounting Policies - Property and Equipment (Details)	12 Months Ended
	Dec. 31, 2016
New aircraft
Property and Equipment
Depreciable Life	18 years
Residual Value (as a percent)	30.00%
Used Aircraft, rotable spares, and spare engines | Minimum
Property and Equipment
Residual Value (as a percent)	0.00%
Used Aircraft, rotable spares, and spare engines | Maximum
Property and Equipment
Depreciable Life	18 years
Residual Value (as a percent)	30.00%
Ground equipment
Property and Equipment
Residual Value (as a percent)	0.00%
Ground equipment | Maximum
Property and Equipment
Depreciable Life	10 years
Office equipment
Property and Equipment
Residual Value (as a percent)	0.00%
Office equipment | Maximum
Property and Equipment
Depreciable Life	7 years
Leasehold improvements
Property and Equipment
Residual Value (as a percent)	0.00%
Leasehold improvements | Maximum
Property and Equipment
Depreciable Life	15 years
Buildings
Property and Equipment
Residual Value (as a percent)	0.00%
Buildings | Minimum
Property and Equipment
Depreciable Life	20 years
Buildings | Maximum
Property and Equipment
Depreciable Life	39 years 6 months

Nature of Operations and Summ38

Nature of Operations and Summary of Significant Accounting Policies - Long-Lived Assets (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2016USD ($)aircraft	Dec. 31, 2017aircraft	Dec. 31, 2016USD ($)item	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Sep. 07, 2005USD ($)
Impairment of Long Lived and Intangible Assets
Property and equipment and related assets	$ 5,140,005		$ 5,140,005	$ 5,556,728
Intangible assets	8,249		8,249	10,499	$ 12,748
Proceeds from settlement of residual value guarantee aircraft agreements	$ 125,000		$ 90,000
CRJ 200
Impairment of Long Lived and Intangible Assets
Number of aircraft removed from service | aircraft	76
Proceeds from settlement of residual value guarantee aircraft agreements	$ 125,000
ERJ 145
Impairment of Long Lived and Intangible Assets
Number of extension rights | item			2
Term of extension rights			1 year
Atlantic Southeast Airlines Inc.
Impairment of Long Lived and Intangible Assets
Intangible assets related to acquisition of Atlantic Southeast						$ 33,700
Period for amortization of intangible assets			15 years
Accumulated amortization expense	$ 25,500		$ 25,500	$ 23,300
Forecast | CRJ 200
Impairment of Long Lived and Intangible Assets
Number of aircraft removed from service | aircraft		46
Forecast | ERJ 145
Impairment of Long Lived and Intangible Assets
Number of aircraft removed from service | aircraft		45

Nature of Operations and Summ39

Nature of Operations and Summary of Significant Accounting Policies - Capitalized Interest (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Capitalized Interest
Capitalized interest costs	$ 1.5	$ 2.2	$ 1.8

Nature of Operations and Summ40

Nature of Operations and Summary of Significant Accounting Policies - Passenger and Ground Handling Revenues (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
ExpressJet United Express ERJ Agreement and ExpressJet American ERJ145 Agreement
Other Revenue Items
Deemed rental income under code-share agreement	$ 516	$ 504.9	$ 497

Nature of Operations and Summ41

Nature of Operations and Summary of Significant Accounting Policies - Agreements (Details) - aircraft	1 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Agreements with other airlines
Number of aircraft held by entity			685
CRJ 200
Agreements with other airlines
Number of aircraft held by entity			215
Number of aircraft removed from service	76
CRJ 200 | Forecast
Agreements with other airlines
Number of aircraft removed from service		46
CRJ 200 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract			22
CRJ 700
Agreements with other airlines
Number of aircraft held by entity			139
CRJ 700 | Forecast
Agreements with other airlines
Number of aircraft operated in the existing fleet		49
CRJ 900
Agreements with other airlines
Number of aircraft held by entity			64
E 175
Agreements with other airlines
Number of aircraft held by entity			86
ERJ 135
Agreements with other airlines
Number of aircraft held by entity			9
ERJ 145
Agreements with other airlines
Number of aircraft held by entity			158
ERJ 145 | Forecast
Agreements with other airlines
Number of aircraft removed from service		45
EMB 120
Agreements with other airlines
Number of aircraft held by entity			14
ERJ145/135 | Forecast
Agreements with other airlines
Number of aircraft removed from service		59
Delta Connection Agreements | Sky West Airlines Inc
Agreements with other airlines
Term of agreement			3 years 8 months 12 days
Delta Connection Agreements | ExpressJet
Agreements with other airlines
Term of agreement			2 years 9 months 18 days
Delta Connection Agreements | CRJ 200 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract			50
Delta Connection Agreements | CRJ 200 | ExpressJet
Agreements with other airlines
Number of aircraft under contract			38
Delta Connection Agreements | CRJ 700 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract			27
Delta Connection Agreements | CRJ 700 | ExpressJet
Agreements with other airlines
Number of aircraft under contract			35
Delta Connection Agreements | CRJ 900 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract			36
Delta Connection Agreements | CRJ 900 | ExpressJet
Agreements with other airlines
Number of aircraft under contract			28
Delta Connection Agreements | E 175 | Forecast
Agreements with other airlines
Number of additional aircrafts into service		6
Delta Connection Agreements | E 175 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract			13
Delta Connection Prorate Agreements | Sky West Airlines Inc
Agreements with other airlines
Term of agreement			30 days
Delta Connection Prorate Agreements | CRJ 200 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract			21
United Express Agreements | Sky West Airlines Inc
Agreements with other airlines
Term of agreement			5 years 8 months 12 days
United Express Agreements | CRJ 200 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract			53
United Express Agreements | CRJ 700 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract			35
United Express Agreements | E 175 | Forecast
Agreements with other airlines
Number of additional aircrafts into service		7
United Express Agreements | E 175 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract			58
United ERJ Agreements | ExpressJet
Agreements with other airlines
Term of agreement			10 months 24 days
United ERJ Agreements | ERJ 135 | ExpressJet
Agreements with other airlines
Number of aircraft under contract			5
United ERJ Agreements | ERJ 145 | ExpressJet
Agreements with other airlines
Number of aircraft under contract			140
United Express Prorate Agreement | Sky West Airlines Inc
Agreements with other airlines
Term of agreement			120 days
American Capacity Purchase Agreement | CRJ 200 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract			9
American Capacity Purchase Agreement | CRJ 200 | ExpressJet
Agreements with other airlines
Number of aircraft under contract			11
American Capacity Purchase Agreement | CRJ 700 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract			23
American Capacity Purchase Agreement | CRJ 700 | ExpressJet
Agreements with other airlines
Number of aircraft under contract			10
American Capacity Purchase Agreement | ERJ 145 | ExpressJet
Agreements with other airlines
Number of aircraft under contract			14
American Prorate Agreement | Sky West Airlines Inc
Agreements with other airlines
Term of agreement			120 days
American Prorate Agreement | ExpressJet
Agreements with other airlines
Term of agreement			120 days
American Prorate Agreement | CRJ 200 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract			6
American Prorate Agreement | CRJ 200 | ExpressJet
Agreements with other airlines
Number of aircraft under contract			3
Alaska Capacity Purchase Agreement | E 175 | Forecast
Agreements with other airlines
Number of additional aircrafts into service		5
Alaska Capacity Purchase Agreement | E 175 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract			15
American
Agreements with other airlines
Number of aircraft held by entity			76
American | CRJ 200
Agreements with other airlines
Number of aircraft held by entity			29
American | CRJ 700
Agreements with other airlines
Number of aircraft held by entity			33
American | ERJ 145
Agreements with other airlines
Number of aircraft held by entity			14
Aircraft in scheduled service
Agreements with other airlines
Number of aircraft held by entity			652
Aircraft in scheduled service | CRJ 200
Agreements with other airlines
Number of aircraft held by entity			213
Aircraft in scheduled service | CRJ 700
Agreements with other airlines
Number of aircraft held by entity			130
Aircraft in scheduled service | CRJ 900
Agreements with other airlines
Number of aircraft held by entity			64
Aircraft in scheduled service | E 175
Agreements with other airlines
Number of aircraft held by entity			86
Aircraft in scheduled service | ERJ 135
Agreements with other airlines
Number of aircraft held by entity			5
Aircraft in scheduled service | ERJ 145
Agreements with other airlines
Number of aircraft held by entity			154
Aircraft in scheduled service | ERJ145/135
Agreements with other airlines
Number of aircraft held by entity			159

Nature of Operations and Summ42

Nature of Operations and Summary of Significant Accounting Policies - Net Income (Loss) Per Share and Fair Value (Details) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016USD ($)$ / sharesshares	Sep. 30, 2016USD ($)$ / sharesshares	Jun. 30, 2016USD ($)$ / sharesshares	Mar. 31, 2016USD ($)$ / sharesshares	Dec. 31, 2015USD ($)$ / sharesshares	Sep. 30, 2015USD ($)$ / sharesshares	Jun. 30, 2015USD ($)$ / sharesshares	Mar. 31, 2015USD ($)$ / sharesshares	Dec. 31, 2016USD ($)segment$ / sharesshares	Dec. 31, 2015USD ($)$ / sharesshares	Dec. 31, 2014USD ($)$ / sharesshares
Net Income (loss) Per Common Share
Number of outstanding options not included in computation of Diluted EPS (in shares)									2,077,000	505,000	3,191,000
Numerator
Net income (loss) | $	$ (270,244)	$ 41,322	$ 40,244	$ 27,092	$ 40,454	$ 36,268	$ 31,475	$ 9,620	$ (161,586)	$ 117,817	$ (24,154)
Denominator
Denominator for basic earnings per-share weighted average shares	51,757,000	51,627,000	51,418,000	51,218,000	50,880,000	50,616,000	51,357,000	51,457,000	51,505,000	51,077,000	51,237,000
Dilution due to stock options and restricted stock units (in shares)										748,000
Weighted average number of shares for diluted net income per common share	51,757,000	52,471,000	52,194,000	52,014,000	51,657,000	51,282,000	51,971,000	52,392,000	51,505,000	51,825,000	51,237,000
Basic earnings per share (in dollars per share) | $ / shares	$ (5.22)	$ 0.80	$ 0.78	$ 0.53	$ 0.80	$ 0.72	$ 0.61	$ 0.19	$ (3.14)	$ 2.31	$ (0.47)
Diluted earnings per share (in dollars per share) | $ / shares	$ (5.22)	$ 0.79	$ 0.77	$ 0.52	$ 0.78	$ 0.71	$ 0.61	$ 0.18	$ (3.14)	$ 2.27	$ (0.47)
Fair Value of Financial Instruments
Fair value of long-term debt | $	$ 2,566,500				$ 1,939,800				$ 2,566,500	$ 1,939,800
Carrying amount of long-term debt | $	$ 2,545,511				$ 1,927,901				$ 2,545,511	$ 1,927,901
Segment Reporting
Number of operating segments | segment									3

Nature of Operations and Summ43

Nature of Operations and Summary of Significant Accounting Policies - Recent Accounting Pronouncements and Immaterial Error Correction (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Recent Accounting Pronouncements
Unamortized debt issuance costs	$ 25,393	$ 20,902
Accounting Standards Update 2015-03
Recent Accounting Pronouncements
Unamortized debt issuance costs		$ 20,900

Segment Reporting (Details)

Segment Reporting (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Sep. 30, 2015USD ($)	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2016USD ($)segmentaircraft	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Segment Reporting
Number of operating segments | segment									3
Operating revenues	$ 758,017	$ 799,776	$ 801,338	$ 762,075	$ 752,744	$ 794,004	$ 788,417	$ 760,398	$ 3,121,206	$ 3,095,563	$ 3,237,447
Operating expense									3,293,890	2,861,048	3,212,599
Depreciation and amortization expense									284,969	264,507	259,642
Special items									465,649		74,777
Interest expense									78,177	75,850	65,995
Segment profit (loss)									(250,861)	158,665	(41,147)
Identifiable intangible assets, other than goodwill	8,249				10,499				8,249	10,499	12,748
Total assets	5,137,251				4,781,984				5,137,251	4,781,984	4,388,818
Capital expenditures (including non-cash)									$ 1,159,001	715,089	696,923
CRJ 200
Segment Reporting
Number of aircraft lease to third party | aircraft									2
Special items									$ 424,466
SkyWest Airlines
Segment Reporting
Operating revenues									1,935,378	1,848,363	1,873,675
Operating expense									1,886,173	1,630,200	1,758,145
Depreciation and amortization expense									139,159	141,189	162,699
Special items									184,295		57,046
Interest expense									26,211	36,141	39,451
Segment profit (loss)									22,994	182,022	76,079
Total assets	2,343,814				2,300,388				2,343,814	2,300,388	2,475,283
Capital expenditures (including non-cash)									57,761	30,897	137,678
ExpressJet Airlines Inc
Segment Reporting
Operating revenues									1,044,828	1,169,923	1,346,859
Operating expense									1,339,569	1,192,070	1,446,050
Depreciation and amortization expense									83,935	86,382	88,459
Special items									281,354		17,731
Interest expense									6,773	12,091	18,754
Segment profit (loss)									(301,514)	(34,238)	(117,945)
Identifiable intangible assets, other than goodwill	8,249				10,499				8,249	10,499	12,748
Total assets	618,637				1,331,000				618,637	1,331,000	1,386,564
Capital expenditures (including non-cash)									15,396	24,679	23,790
ExpressJet Airlines Inc | CRJ 200
Segment Reporting
Special items									240,200
SkyWest Leasing
Segment Reporting
Operating revenues									141,000	77,277	16,913
Operating expense									68,148	38,778	8,404
Depreciation and amortization expense									61,875	36,936	8,484
Interest expense									45,193	27,618	7,790
Segment profit (loss)									27,659	10,881	719
Total assets	$ 2,174,800				$ 1,150,596				2,174,800	1,150,596	526,971
Capital expenditures (including non-cash)									$ 1,085,844	$ 659,513	$ 535,455

Long-term Debt (Details)

Long-term Debt (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)aircraft	Dec. 31, 2015USD ($)
Long-term Debt
Total long-term debt	$ 2,570,904	$ 1,948,803
Less current maturities	(308,945)	(272,027)
Long-term debt, net of current maturities	$ 2,261,959	$ 1,676,776
Effective interest rate (as a percent)	3.80%	3.70%
Aggregate amounts of principal maturities of long-term debt
2,017	$ 308,945
2,018	286,164
2,019	286,266
2,020	251,265
2,021	236,896
Thereafter	1,201,368
Repayment of debt in cash	16,500	$ 110,800
Total repayment of debt	18,400	145,400
Pre-tax gain	1,279	33,660
Letters of credit and surety bonds outstanding with various banks and surety institutions	$ 87,700	88,900
E 175
Long-term Debt
Number of new aircraft acquired | aircraft	41
Purchase price portion financed through debt issuance (as a percent)	85.00%
Purchase price portion paid with cash (as a percent)	15.00%
Notes payable to banks, due in semi-annual installments, variable interest based on LIBOR, or with interest rates ranging from 2.64% to 2.82% through 2017 to 2020, secured by aircraft
Long-term Debt
Total long-term debt	$ 63,408	108,348
Notes payable to banks, due in semi-annual installments, variable interest based on LIBOR, or with interest rates ranging from 2.64% to 2.82% through 2017 to 2020, secured by aircraft | Minimum
Long-term Debt
Interest rate (as a percent)	2.64%
Notes payable to banks, due in semi-annual installments, variable interest based on LIBOR, or with interest rates ranging from 2.64% to 2.82% through 2017 to 2020, secured by aircraft | Maximum
Long-term Debt
Interest rate (as a percent)	2.82%
Notes payable to a financing company, due in semi-annual installments, variable interest based on LIBOR, or with interest rates ranging from 2.27% to 3.25% through 2017 to 2021, secured by aircraft
Long-term Debt
Total long-term debt	$ 146,266	217,341
Notes payable to a financing company, due in semi-annual installments, variable interest based on LIBOR, or with interest rates ranging from 2.27% to 3.25% through 2017 to 2021, secured by aircraft | Minimum
Long-term Debt
Interest rate (as a percent)	2.27%
Notes payable to a financing company, due in semi-annual installments, variable interest based on LIBOR, or with interest rates ranging from 2.27% to 3.25% through 2017 to 2021, secured by aircraft | Maximum
Long-term Debt
Interest rate (as a percent)	3.25%
Notes payable to banks, due in semi-annual installments plus interest at 6.06% to 6.51% through 2021, secured by aircraft
Long-term Debt
Total long-term debt	$ 86,052	108,069
Notes payable to banks, due in semi-annual installments plus interest at 6.06% to 6.51% through 2021, secured by aircraft | Minimum
Long-term Debt
Interest rate (as a percent)	6.06%
Notes payable to banks, due in semi-annual installments plus interest at 6.06% to 6.51% through 2021, secured by aircraft | Maximum
Long-term Debt
Interest rate (as a percent)	6.51%
Notes payable to a financing company, due in semi-annual installments plus interest at 5.78% to 6.23% through 2017, secured by aircraft
Long-term Debt
Total long-term debt	$ 8,854	17,208
Notes payable to a financing company, due in semi-annual installments plus interest at 5.78% to 6.23% through 2017, secured by aircraft | Minimum
Long-term Debt
Interest rate (as a percent)	5.78%
Notes payable to a financing company, due in semi-annual installments plus interest at 5.78% to 6.23% through 2017, secured by aircraft | Maximum
Long-term Debt
Interest rate (as a percent)	6.23%
Notes payable to banks, due in monthly installments plus interest of 2.68% to 6.86% through 2025, secured by aircraft
Long-term Debt
Total long-term debt	$ 426,389	479,170
Notes payable to banks, due in monthly installments plus interest of 2.68% to 6.86% through 2025, secured by aircraft | Minimum
Long-term Debt
Interest rate (as a percent)	2.68%
Notes payable to banks, due in monthly installments plus interest of 2.68% to 6.86% through 2025, secured by aircraft | Maximum
Long-term Debt
Interest rate (as a percent)	6.86%
Notes payable to banks, due in monthly installments, plus interest at 6.05% through 2020, secured by aircraft
Long-term Debt
Interest rate (as a percent)	6.05%
Total long-term debt	$ 8,998	11,304
Notes payable to banks, due in monthly installments, plus interest at 3.44% through 2019, secured by aircraft
Long-term Debt
Interest rate (as a percent)	3.44%
Total long-term debt	$ 3,280	4,615
Notes payable to banks, due in quarterly installments plus interest at 3.39% to 4.68% through 2028, secured by aircraft
Long-term Debt
Total long-term debt	$ 1,806,981	966,156
Notes payable to banks, due in quarterly installments plus interest at 3.39% to 4.68% through 2028, secured by aircraft | Minimum
Long-term Debt
Interest rate (as a percent)	3.39%
Notes payable to banks, due in quarterly installments plus interest at 3.39% to 4.68% through 2028, secured by aircraft | Maximum
Long-term Debt
Interest rate (as a percent)	4.68%
Notes payable to banks, due in monthly installments, plus interest based on LIBOR at 3.54% through 2017, secured by aircraft
Long-term Debt
Interest rate (as a percent)	3.54%
Total long-term debt	$ 4,666	14,538
Notes payable to banks due in monthly installments, interest based on LIBOR interest at 3.30% through 2019, secured by spare engines
Long-term Debt
Interest rate (as a percent)	3.30%
Total long-term debt	$ 16,010	22,054
Line of credit
Long-term Debt
Effective interest rate (as a percent)	3.30%
Aggregate amounts of principal maturities of long-term debt
Maximum borrowing capacity	$ 75,000	$ 25,000
Amount outstanding	0
Letters of credit	6,500
Current borrowing capacity	$ 68,500
LIBOR | Line of credit
Long-term Debt
Basis spread on variable rate	2.50%

Long-term Debt - ASU 2015-03 (D

Long-term Debt - ASU 2015-03 (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Current portion long-term debt	$ 308,945	$ 272,027
Long-term debt, net of current maturities	2,261,959	1,676,776
Total long-term debt	2,570,904	1,948,803
Unamortized debt issue cost, net	(25,393)	(20,902)
Total long-term debt, net of debt issue costs	$ 2,545,511	1,927,901
Accounting Standards Update 2015-03
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Unamortized debt issue cost, net		$ (20,900)

Income Taxes - Provision (Detai

Income Taxes - Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current tax provision (benefit):
Federal	$ (3,801)	$ 3,801	$ (176)
State	111	1,035	838
Foreign			2,081
Total current payable	(3,690)	4,836	2,743
Deferred tax provision (benefit):
Federal	(77,430)	66,430	4,697
State	(6,106)	5,239	371
Total deferred payable	(83,536)	71,669	5,068
Provision for income taxes	$ (87,226)	$ 76,505	$ 7,811

Income Taxes - Reconciliation (

Income Taxes - Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Taxes
Statutory Federal income tax rate (as a percent)	35.00%
Reconciliation between the statutory federal income tax rate of 35% and the effective rate which is derived by dividing the provision for income taxes by income (loss) before income taxes
Computed provision (benefit) for income taxes at the statutory rate	$ (87,084)	$ 68,013	$ (5,720)
State income tax provision (benefit), net of federal income tax benefit	(5,768)	5,416	(107)
Non-deductible expenses	3,552	3,641	3,865
Valuation allowance changes affecting the provision for income taxes	751	(899)	5,981
Foreign income taxes, net of federal & state benefit			1,973
Other, net	1,323	334	1,819
Provision for income taxes	(87,226)	76,505	$ 7,811
Deferred tax assets:
Intangible Asset	4,983	30,369
Accrued benefits	48,482	47,514
Net operating loss carryforward	286,389	82,211
AMT credit carryforward	17,589	21,391
Deferred aircraft credits	60,415	55,544
Accrued reserves and other	47,906	24,575
Total deferred tax assets	465,764	261,604
Valuation allowance	(8,877)	(8,126)
Deferred tax liabilities:
Accelerated depreciation	(1,022,291)	(902,322)
Total deferred tax liabilities	(1,022,291)	(902,322)
Net deferred tax liability	$ 565,404	$ 648,844

Income Taxes - Net Operating Lo

Income Taxes - Net Operating Losses and Tax Rates (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Net operating losses
State income tax rate (as a percent)	2.60%
Statutory Federal income tax rate (as a percent)	35.00%
Alternative minimum tax credit without expiration	$ 17,589	$ 21,391
Valuation allowance on acquired non-amortizable intangible tax assets and other tax assets	8,877	8,126
Domestic tax authority
Net operating losses
Operating loss carryforward	763,900	189,000
State
Net operating losses
Operating loss carryforward	$ 469,200	$ 352,200

Commitments and Contingencies50

Commitments and Contingencies (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)aircraft	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Future minimum rental payments required under operating leases
2,017	$ 191,292
2,018	155,799
2,019	123,308
2,020	135,386
2,021	112,535
Thereafter	236,503
Total future lease obligations	$ 954,823
Number of aircraft leased by the entity | aircraft	415
Rental expense for non-cancelable aircraft operating leases	$ 262,602	$ 273,696	$ 305,334
Minimum rental expense for airport station rents	$ 31,400	$ 35,100	$ 29,000
Maximum
Future minimum rental payments required under operating leases
Lease contract term (in years)	9 years

Commitments and Contingencies -

Commitments and Contingencies - Concentration Risks and Employees Under Collective Bargaining Agreements (Details)	12 Months Ended
	Dec. 31, 2016USD ($)employee	Dec. 31, 2015USD ($)	Dec. 31, 2014
Concentration Risk and Significant Customers
Allowance for doubtful accounts | $	$ 173,000	$ 187,000
Atlantic Southeast pilots and ExpressJet Delaware pilots
Concentration Risk and Significant Customers
Labor agreement, contract extension term (in years)	2 years
Revenue from rights, concentration risk | Customer concentration risk | Delta, United, and Continental Combined
Concentration Risk and Significant Customers
Concentration risk (as a percent)	85.40%	86.90%	88.70%
Full-time equivalent number of employees
Concentration Risk and Significant Customers
Number of employees	16,900
Full-time equivalent number of employees | Unionized employees
Concentration Risk and Significant Customers
Concentration risk (as a percent)	33.40%
Full-time equivalent number of employees | Unionized employees | Atlantic Southeast Pilots
Concentration Risk and Significant Customers
Number of employees	1,238
Full-time equivalent number of employees | Unionized employees | Atlantic Southeast Flight Attendants
Concentration Risk and Significant Customers
Number of employees	833
Full-time equivalent number of employees | Unionized employees | Atlantic Southeast Flight Controllers
Concentration Risk and Significant Customers
Number of employees	68
Full-time equivalent number of employees | Unionized employees | Atlantic Southeast Mechanics
Concentration Risk and Significant Customers
Number of employees	366
Full-time equivalent number of employees | Unionized employees | Atlantic Southeast Stock Clerks
Concentration Risk and Significant Customers
Number of employees	35
Full-time equivalent number of employees | Unionized employees | ExpressJet Delaware Pilots
Concentration Risk and Significant Customers
Number of employees	1,496
Full-time equivalent number of employees | Unionized employees | ExpressJet Delaware Flight Attendants
Concentration Risk and Significant Customers
Number of employees	783
Full-time equivalent number of employees | Unionized employees | ExpressJet Delaware Mechanics
Concentration Risk and Significant Customers
Number of employees	730
Full-time equivalent number of employees | Unionized employees | ExpressJet Delaware Dispatchers
Concentration Risk and Significant Customers
Number of employees	47
Full-time equivalent number of employees | Unionized employees | ExpressJet Delaware Stock Clerks
Concentration Risk and Significant Customers
Number of employees	47

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Fair Value Measurements
Marketable securities	$ 409,898	$ 286,668
Fair Value of Financial Instruments
Fair value of long-term debt	2,566,500	1,939,800
Carrying amount of long-term debt	2,545,511	1,927,901
Auction Rate Securities
Changes in assets measured at fair value on a recurring basis using significant unobservable inputs (level 3)
Balance	2,321
Total realized and unrealized gains or (losses) included in earnings	161
Total realized and unrealized gains or (losses) included in other comprehensive income	18
Settlements	(2,500)
Recurring | Fair value
Fair Value Measurements
Marketable securities	409,898
Cash, Cash Equivalents and Restricted Cash	155,009	211,251
Auction Rate Securities		2,321
Total Assets Measured at Fair Value	564,907	500,240
Recurring | Fair value | Bonds and bond funds
Fair Value Measurements
Marketable securities	409,885	286,637
Recurring | Fair value | Asset-backed securities
Fair Value Measurements
Marketable securities	13	286,668
Recurring | Fair value | Commercial paper
Fair Value Measurements
Marketable securities		31
Recurring | Level 1
Fair Value Measurements
Cash, Cash Equivalents and Restricted Cash	155,009	211,251
Total Assets Measured at Fair Value	155,009	211,251
Recurring | Level 2
Fair Value Measurements
Marketable securities	409,898
Total Assets Measured at Fair Value	409,898	286,668
Recurring | Level 2 | Bonds and bond funds
Fair Value Measurements
Marketable securities	409,885	286,637
Recurring | Level 2 | Asset-backed securities
Fair Value Measurements
Marketable securities	$ 13	286,668
Recurring | Level 2 | Commercial paper
Fair Value Measurements
Marketable securities		31
Recurring | Level 3
Fair Value Measurements
Auction Rate Securities		2,321
Total Assets Measured at Fair Value		$ 2,321

Investment in Other Companies (

Investment in Other Companies (Details) - Trip Linhas Aereas $ in Millions	12 Months Ended
	Dec. 31, 2014USD ($)
Investments in other companies
Company's investment balance	$ 42
Gain (loss) on equity method investments	$ 24.9
Common Stock
Investments in other companies
Annual rate of return used to calculate the put option price (as a percent)	20.00%

Special Items (Details)

Special Items (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2016USD ($)aircraft	Dec. 31, 2017aircraft	Dec. 31, 2016USD ($)item	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Total Special items			$ 465,649		$ 74,777
Aircraft rentals			262,602	$ 273,696	305,334
Proceeds from settlement of residual value guarantee aircraft agreements	$ 125,000		90,000
Paint facility
Total Special items					4,800
CRJ 200
Number of aircraft removed from service | aircraft	76
Total Special items			$ 424,466
Proceeds from settlement of residual value guarantee aircraft agreements	$ 125,000
CRJ 200 | Forecast
Number of aircraft removed from service | aircraft		46
EMB 120
Total Special items					57,046
ERJ 145
Number of extension rights | item			2
Term of extension rights			1 year
Total Special items			$ 41,183		12,931
Estimated fair value	$ 41,200		41,200		11,400
Aircraft rentals					1,500
ERJ 145 | Forecast
Number of aircraft removed from service | aircraft		45
SkyWest Airlines
Total Special items			184,295		57,046
Proceeds from settlement of residual value guarantee aircraft agreements			90,000
ExpressJet Airlines Inc
Total Special items			281,354		$ 17,731
ExpressJet Airlines Inc | CRJ 200
Total Special items			$ 240,200

Capital Transactions - Preferre

Capital Transactions - Preferred Stock (Details) - shares	Dec. 31, 2016	Dec. 31, 2015
Preferred Stock
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock outstanding (in shares)	0

Capital Transactions - Stock Co

Capital Transactions - Stock Compensation (Details) - USD ($)	May 04, 2010	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2013
Assumptions used to determine value of the shares purchased under the stock purchase plan using Black-Scholes option pricing model
Performance period		90 days
Compensation expenses
Stock based compensation expense		$ 7,568,000	$ 5,368,000	$ 5,318,000
Maximum
Assumptions used to determine value of the shares purchased under the stock purchase plan using Black-Scholes option pricing model
Award percentage		150.00%
Minimum
Assumptions used to determine value of the shares purchased under the stock purchase plan using Black-Scholes option pricing model
Award percentage		0.00%
Stock options and restricted stock
Compensation expenses
Total unrecognized compensation cost					$ 9,700,000
Unrecognized compensation cost recognized over a weighted average period (in years)		1 year 8 months 12 days
Employee stock option
Share-Based Compensation
Options outstanding (in shares)		1,064,429	2,888,074	3,407,575	819,981	1,064,429	3,407,575
Assumptions used to determine value of the shares purchased under the stock purchase plan using Black-Scholes option pricing model
Weighted average fair value of option grants		$ 5.31
Compensation expenses
Period from grant date after which stock options become exercisable, minimum (in months)		6 months
Period from grant date within which incentive stock options are exercisable, maximum (in years)		7 years
Number of Options
Outstanding at the beginning of the period (in shares)		1,064,429	2,888,074	3,407,575
Granted (in shares)		206,021	267,433	255,503
Exercised (in shares)		(351,296)	(544,917)	(6,701)
Cancelled (in shares)		(99,173)	(1,546,161)	(768,303)
Outstanding at the end of the period (in shares)		819,981	1,064,429	2,888,074
Exercisable (in shares)					263,851	484,747
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)		$ 13.64	$ 16.46	$ 17.99
Granted (in dollars per share)		14.90	13.63	11.96
Exercised (in dollars per share)		14.17	14.68	12.10
Cancelled (in dollars per share)		14.90	18.53	6.81
Outstanding at the end of the period (in dollars per share)		$ 13.58	$ 13.64	$ 16.46
Exercisable (in dollars per share)					$ 13.76	$ 14.46
Weighted Average Remaining Contractual Term
Outstanding, Weighted Average Remaining Contractual Term (in years)		4 years 4 months 24 days	3 years 8 months 12 days
Exercisable, Weighted Average Remaining Contractual Term (in years)		2 years 9 months 18 days	1 year 8 months 12 days
Aggregate Intrinsic Value
Average intrinsic value of shares outstanding					$ 18,756,900	$ 5,726.70
Average intrinsic value of shares exercisable					$ 5,985,500		$ 2,212.50
Total intrinsic value of options exercised		$ 4,250,000	$ 1,800,000	$ 30,000
Non-vested stock options
Non-vested shares at beginning of year (in shares)		579,682
Granted (in shares)		206,021	267,433	255,503
Vested (in shares)		(209,419)
Cancelled (in shares)		(20,154)
Non-vested shares at end of year (in shares)		556,130	579,682
Weighted Average Grant-Date Fair Value
Non-vested shares at beginning of year (in dollars per share)		$ 4.75
Granted (in dollars per share)		5.31
Vested (in dollars per share)		5
Cancelled (in dollars per share)		4.96
Non-vested shares at end of year (in dollars per share)		$ 4.86	$ 4.75
Restricted stock
Assumptions used to determine value of the shares purchased under the stock purchase plan using Black-Scholes option pricing model
Granted (in shares)		384,148	408,163	312,749
Number of shares
Nonvested shares at the beginning of the period (in shares)		809,299	723,176	733,591
Granted (in shares)		384,148	408,163	312,749
Vested (in shares)		(215,146)	(215,856)	(284,891)
Cancelled (in shares)		(51,370)	(106,184)	(38,273)
Nonvested shares at the end of the period (in shares)		926,931	809,299	723,176
Weighted Average Grant-Date Fair Value
Nonvested shares at the beginning of the period (in dollars per share)		$ 13.13	$ 12.70	$ 13.79
Granted (in dollars per share)		14.81	13.57	12
Vested (in dollars per share)		13.29	13.06	14.74
Cancelled (in dollars per share)		13.72	13.52	12.83
Nonvested shares at the end of the period (in dollars per share)		$ 13.65	$ 13.13	$ 12.70
Restricted stock | Director
Assumptions used to determine value of the shares purchased under the stock purchase plan using Black-Scholes option pricing model
Granted (in shares)		42,624	36,950	44,631
Number of shares
Granted (in shares)		42,624	36,950	44,631
Weighted Average Grant-Date Fair Value
Granted (in dollars per share)		$ 14.78	$ 14.05	$ 12.10
Performance share units
Assumptions used to determine value of the shares purchased under the stock purchase plan using Black-Scholes option pricing model
Granted (in shares)		183,577	222,583
Performance period		3 years
Number of shares
Nonvested shares at the beginning of the period (in shares)		202,829
Granted (in shares)		183,577	222,583
Cancelled (in shares)		(22,413)	(19,754)
Nonvested shares at the end of the period (in shares)		363,993	202,829
Weighted Average Grant-Date Fair Value
Nonvested shares at the beginning of the period (in dollars per share)		$ 13.62
Granted (in dollars per share)		14.89	13.61
Cancelled (in dollars per share)		14.16	13.51
Nonvested shares at the end of the period (in dollars per share)		$ 14.23	$ 13.62
Long Term Incentive Plan 2010
Share-Based Compensation
Number of shares authorized	5,150,000
Assumptions used to determine value of the shares purchased under the stock purchase plan using Black-Scholes option pricing model
Vesting period		3 years	3 years	3 years
Long Term Incentive Plan 2010 | Employee stock option
Share-Based Compensation
Minimum incentive stock option exercise price, expressed as a percentage of common stock grant date market value	100.00%
Assumptions used to determine value of the shares purchased under the stock purchase plan using Black-Scholes option pricing model
Expected annual dividend rate (as a percent)		1.08%	1.18%	1.32%
Risk-free interest rate (as a percent)		1.15%	1.62%	1.50%
Average expected life (years)		5 years 8 months 12 days	5 years 8 months 12 days	5 years 9 months 18 days
Expected volatility of common stock (as a percent)		0.412%	0.401%	0.431%
Forfeiture rate (as a percent)		0.00%	0.00%	0.00%
Weighted average fair value of option grants		$ 5.27	$ 4.75	$ 4.47
Number of Options
Granted (in shares)		206,021	267,433	255,503
Non-vested stock options
Granted (in shares)		206,021	267,433	255,503
Weighted Average Grant-Date Fair Value
Granted (in dollars per share)		$ 5.27	$ 4.75	$ 4.47
Long Term Incentive Plan 2010 | Restricted stock
Assumptions used to determine value of the shares purchased under the stock purchase plan using Black-Scholes option pricing model
Granted (in shares)		380,358
Vesting period		3 years
Number of shares
Granted (in shares)		380,358
Weighted Average Grant-Date Fair Value
Granted (in dollars per share)		$ 14.81
Long Term Incentive Plan 2010 | Restricted stock | Director
Assumptions used to determine value of the shares purchased under the stock purchase plan using Black-Scholes option pricing model
Granted (in shares)		380,358
Number of shares
Granted (in shares)		380,358

Capital Transactions - Informat

Capital Transactions - Information About Stock Options Outstanding (Details)	12 Months Ended
	Dec. 31, 2016$ / sharesshares
$8 to $11
Stock options, exercise price
Exercise price range, low end of range (in dollars per share)	$ 8
Exercise price range, high end of range (in dollars per share)	$ 11
Options Outstanding
Number of options outstanding (in shares) | shares	19,458
Options outstanding, Weighted Average Remaining Contractual Life	4 years 4 months 24 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 11.10
$12 to $14
Stock options, exercise price
Exercise price range, low end of range (in dollars per share)	12
Exercise price range, high end of range (in dollars per share)	$ 14
Options Outstanding
Number of options outstanding (in shares) | shares	732,048
Options outstanding, Weighted Average Remaining Contractual Life	4 years 7 months 6 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 13.43
Options Exercisable
Number of options Exercisable (in shares) | shares	205,087
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 13.26
$15 to $19
Stock options, exercise price
Exercise price range, low end of range (in dollars per share)	15
Exercise price range, high end of range (in dollars per share)	$ 19
Options Outstanding
Number of options outstanding (in shares) | shares	68,475
Options outstanding, Weighted Average Remaining Contractual Life	1 year 10 months 24 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 15.88
Options Exercisable
Number of options Exercisable (in shares) | shares	58,764
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 15.54
$8 to $19
Stock options, exercise price
Exercise price range, low end of range (in dollars per share)	8
Exercise price range, high end of range (in dollars per share)	$ 19
Options Outstanding
Number of options outstanding (in shares) | shares	819,981
Options outstanding, Weighted Average Remaining Contractual Life	4 years 4 months 24 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 13.58
Options Exercisable
Number of options Exercisable (in shares) | shares	263,851
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 13.76

Retirement Plans and Employee58

Retirement Plans and Employee Stock Purchase Plans - Retirement Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
SkyWest Plan
Retirement Plans
Service period required to be completed to be eligible to participate in plan	90 days
Required age for an employee to be eligible to participate in plan	18 years
Percentage of employer matching contribution based on length of service	100.00%
Company's combined contributions	$ 23.2	$ 20.4	$ 19.3
SkyWest Plan | Pilot employees
Retirement Plans
Percentage of participant's compensation eligible for employer's matching contribution based upon length of service, threshold one	2.00%
Percentage of participant's compensation eligible for employer's matching contribution based upon length of service, threshold two	4.00%
Percentage of participant compensation eligible for employer's matching contribution based upon length of service, threshold three	6.00%
SkyWest Plan | Non-pilot employees
Retirement Plans
Percentage of participant's compensation eligible for employer's matching contribution based upon length of service, threshold one	3.00%
Percentage of participant's compensation eligible for employer's matching contribution based upon length of service, threshold two	5.00%
Percentage of participant compensation eligible for employer's matching contribution based upon length of service, threshold three	7.00%
Atlantic Southeast and the ExpressJet Plans
Retirement Plans
Service period required to be completed to be eligible to participate in plan	90 days
Required age for an employee to be eligible to participate in plan	18 years
Company's combined contributions	$ 21	$ 24	$ 27.2
Atlantic Southeast Plan
Retirement Plans
Maximum percentage of participant's total compensation eligible for employer matching contribution	6.00%
Minimum service period required to be completed for eight percent matching contribution by the employer	10 years
Maximum percentage of participant's total compensation eligible for employer matching contribution after requisite service period	8.00%
Percentage of vesting for plan participants' elective deferrals and rollover amounts	100.00%
Atlantic Southeast Plan | Minimum
Retirement Plans
Percentage of employer matching contribution based on length of service	20.00%
Percentage of vesting of company matching contribution based on length of service	10.00%
Atlantic Southeast Plan | Maximum
Retirement Plans
Percentage of employer matching contribution based on length of service	75.00%
Percentage of vesting of company matching contribution based on length of service	100.00%

Retirement Plans and Employee59

Retirement Plans and Employee Stock Purchase Plans - Employee Stock Purchase Plans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Employee Stock Purchase Plans
Service period required to be completed for an employee to be eligible to participate in plan, minimum	90 days
Ownership interest in Company common stock to disqualify employee from participation in plan, maximum (as a percent)	5.00%
Maximum percentage of base salary which can be contributed by the employees	15.00%
Maximum amount of base salary which can be contributed annually by the employees	$ 25,000
Discount rate at which common stock can be purchased by the plan participant (as a percent)	5.00%
Summary of purchases made under the 2010 and 1995 Employee Stock Purchase Plans
Number of shares purchased	151,531	254,098	295,035
Average price of shares purchased (in dollars per share)	$ 20.87	$ 13.50	$ 12.72
2009 Stock Purchase Plan
Summary of purchases made under the 2010 and 1995 Employee Stock Purchase Plans
Stock based compensation expense	$ 0	$ 0	$ 0

Stock Repurchase (Details)

Stock Repurchase (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2017	Dec. 31, 2015	Dec. 31, 2014
Common stock repurchased (in shares)		1.3	0.7
Common stock repurchased, value		$ 18.7	$ 8.4
Weighted average price per share of common stock (in dollars per share)		$ 14.98	$ 12.54
Subsequent event
Common stock authorized for repurchase, maximum (in shares)	100
Stock repurchase program year	3 years

Related-Party Transactions (Det

Related-Party Transactions (Details)	12 Months Ended
	Dec. 31, 2016USD ($)aircraft	Dec. 31, 2012aircraft	Dec. 31, 2015USD ($)
Zions Bancorporation
Related Party Transactions
Refinancing term		5 years
Cash balance with related party | $	$ 116,000,000		$ 65,000,000
Investment balance with related party | $	$ 121,600,000		$ 121,600,000
Zions Bancorporation | CRJ 200
Related Party Transactions
Equity participation in leveraged leases on number of aircraft	1
Number of refinanced aircraft		5
Zions Bancorporation | CRJ 700
Related Party Transactions
Equity participation in leveraged leases on number of aircraft	2
Number of refinanced aircraft		2
Affiliated entity
Related Party Transactions
Purchase from related party | $	$ 244,540

Quarterly Financial Data (Una62

Quarterly Financial Data (Unaudited) (Details) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016USD ($)$ / sharesshares	Sep. 30, 2016USD ($)$ / sharesshares	Jun. 30, 2016USD ($)$ / sharesshares	Mar. 31, 2016USD ($)$ / sharesshares	Dec. 31, 2015USD ($)$ / sharesshares	Sep. 30, 2015USD ($)$ / sharesshares	Jun. 30, 2015USD ($)$ / sharesshares	Mar. 31, 2015USD ($)$ / sharesshares	Dec. 31, 2016USD ($)$ / sharesitemshares	Dec. 31, 2015USD ($)$ / sharesshares	Dec. 31, 2014USD ($)$ / sharesshares
Quarterly Financial Data (Unaudited)
Operating revenues	$ 758,017	$ 799,776	$ 801,338	$ 762,075	$ 752,744	$ 794,004	$ 788,417	$ 760,398	$ 3,121,206	$ 3,095,563	$ 3,237,447
Operating income	(404,464)	85,834	84,137	61,809	52,212	78,296	69,932	34,075	(172,684)	234,515	24,848
Net income (loss)	$ (270,244)	$ 41,322	$ 40,244	$ 27,092	$ 40,454	$ 36,268	$ 31,475	$ 9,620	$ (161,586)	$ 117,817	$ (24,154)
Net income (loss) per common share:
Basic (in dollars per share) | $ / shares	$ (5.22)	$ 0.80	$ 0.78	$ 0.53	$ 0.80	$ 0.72	$ 0.61	$ 0.19	$ (3.14)	$ 2.31	$ (0.47)
Diluted (in dollars per share) | $ / shares	$ (5.22)	$ 0.79	$ 0.77	$ 0.52	$ 0.78	$ 0.71	$ 0.61	$ 0.18	$ (3.14)	$ 2.27	$ (0.47)
Weighted average common shares:
Basic (in shares) | shares	51,757	51,627	51,418	51,218	50,880	50,616	51,357	51,457	51,505	51,077	51,237
Diluted (in shares) | shares	51,757	52,471	52,194	52,014	51,657	51,282	51,971	52,392	51,505	51,825	51,237
Special Charge									$ 465,649		$ 74,777
Number of seats on aircraft | item									50

SCHEDULE II_VALUATION AND QUA63

SCHEDULE II—VALUATION AND QUALIFYING ACCOUNTS (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)item	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
VALUATION AND QUALIFYING ACCOUNTS
Balance at Beginning of Year	$ 14,120	$ 11,914	$ 10,232
Additions Charged to Costs and Expenses	26,564	2,345	1,682
Deductions	(14)	(139)
Balance at End of Year	$ 40,670	14,120	11,914
Number of seats on aircraft | item	50
Allowance for inventory obsolescence
VALUATION AND QUALIFYING ACCOUNTS
Balance at Beginning of Year	$ 13,933	11,588	10,138
Additions Charged to Costs and Expenses	26,564	2,345	1,450
Balance at End of Year	40,497	13,933	11,588
Allowance for doubtful accounts receivable
VALUATION AND QUALIFYING ACCOUNTS
Balance at Beginning of Year	187	326	94
Additions Charged to Costs and Expenses			232
Deductions	(14)	(139)
Balance at End of Year	$ 173	$ 187	$ 326