SkyWest (SKYW) 10-K 26 Feb 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2015	Feb. 16, 2016	Jun. 30, 2015
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, 2015
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Public Float			$ 759,240,572
Entity Common Stock, Shares Outstanding		51,127,542
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	FY

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
CURRENT ASSETS:
Cash and cash equivalents	$ 203,035	$ 132,275
Marketable securities	286,668	415,273
Restricted cash	8,216	11,582
Income tax receivable	2,871	2,779
Receivables, net	62,162	83,099
Inventories, net	140,312	137,452
Prepaid aircraft rents	195,216	196,348
Deferred tax assets	100,730	94,385
Other current assets	18,360	16,308
Total current assets	1,017,570	1,089,501
PROPERTY AND EQUIPMENT:
Aircraft and rotable spares	5,242,790	4,608,663
Deposits on aircraft	38,150	40,000
Buildings and ground equipment	275,788	274,900
Total property and equipment, gross	5,556,728	4,923,563
Less-accumulated depreciation and amortization	(2,085,981)	(1,902,375)
Total property and equipment, net	3,470,747	3,021,188
OTHER ASSETS
Intangible assets, net	10,499	12,748
Non-current prepaid aircraft rents	229,180	201,502
Other assets	74,890	84,989
Total other assets	314,569	299,239
Total assets	4,802,886	4,409,928
CURRENT LIABILITIES:
Current maturities of long-term debt	272,027	211,821
Accounts payable	279,864	270,097
Accrued salaries, wages and benefits	138,291	138,902
Accrued aircraft rents	3,226	3,303
Taxes other than income taxes	17,176	17,457
Other current liabilities	40,802	42,775
Total current liabilities	751,386	684,355
OTHER LONG-TERM LIABILITIES	56,191	49,625
LONG-TERM DEBT, net of current maturities	1,676,776	1,533,990
DEFERRED INCOME TAXES PAYABLE	749,575	669,385
DEFERRED AIRCRAFT CREDITS	$ 62,523	$ 72,227
COMMITMENTS AND CONTINGENCIES (Note 5)
STOCKHOLDERS' EQUITY:
Common stock, no par value, 120,000,000 shares authorized; 79,020,371 and 77,951,411 shares issued, respectively	$ 641,643	$ 626,521
Retained earnings	1,275,142	1,165,478
Treasury stock, at cost, 28,015,386 and 26,765,386 shares, respectively	(410,090)	(391,364)
Accumulated other comprehensive income (loss)	(260)	(289)
Total stockholders' equity	1,506,435	1,400,346
Total liabilities and stockholders' equity	$ 4,802,886	$ 4,409,928

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2015	Dec. 31, 2014
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	79,020,371	77,951,411
Treasury stock, at cost, shares	28,015,386	26,765,386

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
OPERATING REVENUES:
Passenger	$ 3,030,023	$ 3,168,000	$ 3,239,525
Ground handling and other	65,540	69,447	58,200
Total operating revenues	3,095,563	3,237,447	3,297,725
OPERATING EXPENSES:
Salaries, wages and benefits	1,203,312	1,258,155	1,211,307
Aircraft maintenance, materials and repairs	604,863	682,773	686,381
Aircraft rentals	273,696	305,334	325,360
Depreciation and amortization	264,507	259,642	245,005
Aircraft fuel	118,124	193,247	193,513
Ground handling services	82,694	123,917	129,119
Special items		74,777
Station rentals and landing fees	54,167	51,024	114,688
Other operating expenses	259,685	263,730	239,241
Total operating expenses	2,861,048	3,212,599	3,144,614
OPERATING INCOME	234,515	24,848	153,111
OTHER INCOME (EXPENSE):
Interest income	1,997	4,096	3,689
Interest expense	(75,850)	(65,995)	(68,658)
Other, net	33,660	20,708	10,390
Total other expense, net	(40,193)	(41,191)	(54,579)
INCOME (LOSS) BEFORE INCOME TAXES	194,322	(16,343)	98,532
PROVISION FOR INCOME TAXES	76,505	7,811	39,576
NET INCOME (LOSS)	$ 117,817	$ (24,154)	$ 58,956
BASIC EARNINGS (LOSS) PER SHARE (in dollars per share)	$ 2.31	$ (0.47)	$ 1.14
DILUTED EARNINGS (LOSS) PER SHARE (in dollars per share)	$ 2.27	$ (0.47)	$ 1.12
Weighted average common shares:
Basic (in shares)	51,077	51,237	51,688
Diluted (in shares)	51,825	51,237	52,422
COMPREHENSIVE INCOME (LOSS):
Net Income (loss)	$ 117,817	$ (24,154)	$ 58,956
Proportionate share of equity method investee foreign currency translation adjustment, net of taxes		(1,129)	66
Net unrealized appreciation (depreciation) on marketable securities, net of taxes	29	(719)	(13)
TOTAL COMPREHENSIVE INCOME (LOSS)	$ 117,846	$ (26,002)	$ 59,009

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock Including Additional Paid in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balance at Dec. 31, 2012	$ 609,763	$ 1,147,117	$ (371,211)	$ 1,506	$ 1,387,175
Balance (in shares) at Dec. 31, 2012	76,713		(25,280)
Increase (Decrease) in Stockholders' Equity
Net Income (loss)		58,956			58,956
Proportionate share of other companies foreign currency translation adjustment, net of tax of $8 and $678 for 2013, and 2014, respectively				66	66
Net unrealized depreciation on marketable securities net of tax of $43, $437 and $18 for 2013, 2014 and 2015, respectively				(13)	(13)
Exercise of common stock options and issuance of restricted stock	$ 835				835
Exercise of common stock options and issuance of restricted stock (in shares)	313
Sale of common stock under employee stock purchase plan	$ 3,696				3,696
Sale of common stock under employee stock purchase plan (in shares)	300
Stock based compensation expense related to the issuance of stock options and restricted stock	$ 4,363				4,363
Tax deficiency from exercise of common stock options	(146)				(146)
Treasury stock purchases			$ (11,739)		(11,739)
Treasury stock purchases (in shares)			(816)
Cash dividends declared ( $0.16 per share)		(8,254)			(8,254)
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 $8 and $678 for 2013, and 2014, respectively				(1,129)	(1,129)
Net unrealized depreciation on marketable securities net of tax of $43, $437 and $18 for 2013, 2014 and 2015, respectively				(719)	(719)
Exercise of common stock options and issuance of restricted stock	$ 287				287
Exercise of common stock options and issuance of restricted stock (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	$ 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 $43, $437 and $18 for 2013, 2014 and 2015, respectively				29	29
Exercise of common stock options and issuance of restricted stock	$ 8,490				8,490
Exercise of common stock options and issuance of restricted stock (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	$ 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)

CONSOLIDATED STATEMENTS OF STO6

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY
Proportionate share of other companies foreign currency translation adjustment, tax		$ 678	$ 8
Net unrealized appreciation (depreciation) on marketable securities, tax	$ (18)	$ (437)	$ 43
Cash dividends declared (in dollars per share)	$ 0.16	$ 0.16	$ 0.16

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income (loss)	$ 117,817	$ (24,154)	$ 58,956
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	264,507	259,642	245,005
Stock based compensation expense	5,368	5,318	4,363
Loss on sale of property and equipment		4,016
Gain from equity ownership in TRIP and AirMekong airlines		(24,922)	(10,830)
Gain from early extinguishment of debt	(33,660)
Capitalized Brasilia EMB-120 engine overhauls		(18,812)	(29,606)
Special items		74,777
Net increase in deferred income taxes	73,844	5,054	38,007
Changes in operating assets and liabilities:
Decrease in restricted cash	3,366	637	7,334
Decrease in receivables	21,076	25,540	18,916
Increase in income tax receivable	(92)	(1,939)	(840)
Increase in inventories	(2,860)	(890)	(24,513)
Increase in other current assets and prepaid aircraft rents	(28,598)	(25,985)	(31,578)
Decrease in deferred aircraft credits	(8,635)	(7,672)	(8,432)
Increase in accounts payable and accrued aircraft rents	9,690	5,852	17,594
Increase (decrease) in other current liabilities	(1,719)	9,077	5,514
NET CASH PROVIDED BY OPERATING ACTIVITIES	420,104	285,539	289,890
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of marketable securities	(1,170,439)	(326,964)	(488,564)
Sales of marketable securities	1,299,069	398,148	557,424
Proceeds from the sale of aircraft, property and equipment	10,308	9,473	293
Proceeds from installment payment of equity shares of TRIP		17,237	16,658
Acquisition of property and equipment:
Aircraft and rotable spare parts	(710,871)	(653,473)	(102,499)
Deposits on aircraft			(40,000)
Buildings and ground equipment	(10,405)	(21,966)	(9,502)
Return of deposits on aircraft	1,850
Decrease (increase) in other assets	10,772	(7,681)	229
NET CASH USED IN INVESTING ACTIVITIES	(569,716)	(585,226)	(65,961)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of long-term debt	591,881	460,600
Principal payments on long-term debt	(354,277)	(185,357)	(171,453)
Net proceeds from issuance of common stock	9,754	2,692	4,385
Purchase of treasury stock	(18,726)	(8,414)	(11,739)
Payment of cash dividends	(8,260)	(8,195)	(8,258)
NET CASH PROVIDED BY (USED IN) FINANCING ACTIVITIES	220,372	261,326	(187,065)
Increase (decrease) in cash and cash equivalents	70,760	(38,361)	36,864
Cash and cash equivalents at beginning of year	132,275	170,636	133,772
CASH AND CASH EQUIVALENTS AT END OF YEAR	203,035	132,275	170,636
Cash paid during the year for:
Interest, net of capitalized amounts	80,657	67,763	71,323
Income taxes	$ 5,104	$ 2,066	$ 3,678

Nature of Operations and Summar

Nature of Operations and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2015
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 airline in the United States. As of December 31, 2015, SkyWest and ExpressJet offered scheduled passenger and air freight service with approximately 3,400 total daily departures to different destinations in the United States, Canada, Mexico and the Caribbean. Additionally, the Company provides ground handling services for other airlines throughout its system. As of December 31, 2015, the Company had a combined fleet of 702 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 *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 were held for sale. For the year ended December 31, 2015, approximately 57.5% of the Company’s aggregate capacity was operated for United, approximately 33.2% was operated for Delta, approximately 6.4% was operated for American, including the flights operated for US Airways, and approximately 2.9% was operated for Alaska. SkyWest Airlines has been a code-share partner with Delta since 1987 and United since 1997. SkyWest Airlines has been a code-share partner with Alaska since 2011 and American since 2012. As of December 31, 2015, SkyWest Airlines operated as a Delta Connection carrier in Salt Lake City and Minneapolis, a United Express carrier in Los Angeles, San Francisco, Denver, Houston, Chicago and the Pacific Northwest, an Alaska carrier in the Pacific Northwest and an American carrier in Los Angeles and Phoenix. On November 17, 2011, the Company’s wholly-owned subsidiaries, Atlantic Southeast Airlines, Inc. and ExpressJet Airlines, Inc., consolidated their operations under a single operating certificate, and on December 31, 2012, Atlantic Southeast Airlines, Inc. and ExpressJet Airlines, Inc. were merged, with the surviving corporation named ExpressJet Airlines, Inc. (the “ExpressJet Combination”). In the following Notes to Consolidated Financial Statements, “Atlantic Southeast” refers to Atlantic Southeast Airlines, Inc. for periods prior to the ExpressJet Combination, “ExpressJet Delaware” refers to ExpressJet Airlines, Inc., a Delaware corporation, for periods prior to the ExpressJet Combination, and “ExpressJet” refers to ExpressJet Airlines, Inc., the Utah corporation resulting from the combination of Atlantic Southeast and ExpressJet Delaware, for periods subsequent to the ExpressJet Combination. Atlantic Southeast had been a code-share partner with Delta in Atlanta since 1984. As of December 31, 2015, ExpressJet operated as a Delta Connection carrier in Atlanta and Detroit, a United Express carrier in Chicago (O’Hare), Cleveland, Newark and Houston and an American carrier in Dallas. Basis of Presentation The Company’s consolidated financial statements include the accounts of SkyWest, Inc. and its subsidiaries, including SkyWest Airlines and ExpressJet, 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, 2015, through the filing date of the Company’s annual report with the U.S. Securities and Exchange Commission. Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America 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 classifie d $8. 2 million and $ 11.6 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, 2015 and 2014, respectively. 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, 2015 and 2014 was as follows (in thousands): 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 $ $ $ $ Gross unrealized Gross unrealized At December 31, 2014 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, 2015 (in thousands): Maturities Amount Year 2016 $ Years 2017 through 2020 As of December 31, 2015 and 2014, the Company had classified $286.7 million and $415.3 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 approximately $2.3 million and $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 and 2014, respectively (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 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, 2015 and 2014 was $13.9 million and $11.6 million, respectively. 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 and rotable spares 3 – 10 years 0 - 30 % Ground equipment 5 – 10 years % Office equipment 5 – 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, 2015, the Company had approximatel y $5. 6 billion of property and equipment and related assets. Additionally, as of December 31, 2015, the Company had approximately $10. 5 m illion 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, 2015 and 2014, the Company had $23.3 million and $21.0 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. The Company did not recognize any impairment charges of long lived assets during 2015 or 2013. 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 the EMB120 long-lived assets, ERJ145 long-lived assets, Saltillo, Mexico paint facility and related 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, 2015, 2014 and 2013, the Company capitalized interest costs of approximately $2.2 million, $1. 8 million, and $1.2 million, respectively. Maintenance The Company operates under a FAA 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 E-175 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 Company used the “deferral method” of accounting for its EMB120 turboprop aircraft engine overhauls, wherein the overhaul costs were capitalized and depreciated to the next estimated overhaul event, or remaining lease term for leased aircraft, whichever was shorter. In 2015, the Company removed all of its EMB120 aircraft from service. 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, “contract flying” or “capacity purchase agreements”) with Delta, United, American and Alaska, the major airline 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 completion of flights 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 a Revenue Sharing Arrangement (referred to as a “revenue-sharing” or “pro rate” 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 pro rate flying agreements when each flight is completed based upon the portion of the pro rate 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. 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 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 following summarizes the significant provisions of each code share agreement the Company has with each major partner: Delta Connection Agreements Number of Pass through costs aircraft under Term / Termination or costs paid directly Agreement agreements Dates by major partner SkyWest Airlines • CRJ 200 - 48 • The contract is scheduled to expire on an individual aircraft basis commencing in 2016 • Fuel Delta Connection • CRJ 700 - 19 • The final aircraft is scheduled to expire in 2022 • Engine Maintenance Agreement (fixed-fee arrangement) • CRJ 900 - 36 • The average remaining term of the aircraft under contract is 3.8 years • Landing fees • Upon expiration, aircraft may be renewed or extended • Station Rents, Deice • Insurance ExpressJet Delta • CRJ 200 - 42 • The contract is scheduled to expire on an individual aircraft basis commencing in 2016 • Fuel Connection • CRJ 700 - 41 • The final aircraft is scheduled to expire in 2022 • Engine Maintenance Agreement (fixed-fee arrangement) • CRJ 900 - 28 • The average remaining term of the aircraft under contract is 3.7 years • Landing fees • Upon expiration, aircraft may be renewed or extended • Station Rents, Deice • Insurance SkyWest Airlines • CRJ 200 - 21 • Terminable with 30 days' notice • None Pro-rate Agreement (revenue-sharing agreement) United Express Agreements Pass through costs Number of or costs paid aircraft under Term / Termination directly by major Agreement agreements Dates partner SkyWest Airlines • CRJ 200 - 57 • The contract is scheduled to expire on an individual aircraft basis commencing in 2016 • Fuel United Express • CRJ 700 - 70 • The final aircraft is scheduled to expire in 2027 • Landing fees Agreements (fixed-fee • E175 - 40 • The average remaining term of the aircraft under contract is 4.3 years • Station Rents, Deice arrangement) • Upon expiration, aircraft may be renewed or extended • Insurance ExpressJet United ERJ • ERJ 135 - 5 • The contract is scheduled to expire on an individual aircraft basis commencing in 2016 • Fuel Agreement (fixed-fee arrangement) • ERJ 145 - 166 • The final aircraft is scheduled to expire in 2017 • Engine Maintenance • The average remaining term of the aircraft under contract is 1.9 years • Landing fees • Upon expiration, aircraft may be renewed or extended • Station Rents, Deice • Insurance SkyWest Airlines United • CRJ 200 - 26 • Terminable with 120 days' notice • None Express Pro-rate Agreement (revenue-sharing arrangement) Alaska Capacity Purchase Agreement Pass through costs Number of or costs paid aircraft under Term / Termination directly by major Agreement agreements Dates partner SkyWest Airlines • CRJ 700 - 9 • The contract is scheduled to expire on an individual aircraft basis commencing in 2016 • Fuel Alaska Agreement • E175 - 5 • The final aircraft is scheduled to expire in 2028 • Landing fees (fixed-fee arrangement) • Upon expiration, aircraft may be renewed or extended • Station Rents, Deice • Insurance American Agreement Pass through costs Number of or costs paid aircraft under Term / Termination directly by major Agreement agreements Dates partner SkyWest Airlines • CRJ 200 - 12 • Scheduled to expire in 2016 • Fuel American Agreement • Upon expiration, aircraft may be renewed or extended • Landing fees (fixed-fee agreement) • Station Rents, Deice • Insurance SkyWest Airlines • CRJ 200 - 5 • Terminable with 120 days' notice • None American Pro-rate Agreement (revenue- sharing agreement) ExpressJet American • CRJ 200 - 11 • Scheduled to expire in 2017 • Fuel Agreement (fixed-fee • ERJ 145 - 16 • Upon expiration, aircraft may be renewed or extended • Landing fees agreement) • Station Rents, Deice • Insurance ExpressJet American Pro-rate • CRJ 200 - 3 • Terminable with 120 days' notice • None Agreement (revenue-sharing agreement) As of December 31, 2015, the Company anticipate d placing an additional 25 E175 aircraft with United, ten additional E175 aircraft with Alaska and 19 E175 aircraft with Delta. The delivery dates for the new aircraft are expected to take place from January 2016 to June 2017. Under the Company’s f ixed- fee a rrangements, the major airline partners compensate the Company for its costs of owning or leasing the aircraft on a monthly basis. 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 ERJ Agreement and ExpressJet American ERJ145 Agreement, the major partner provides the aircraft to the Company for a nominal amount. 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 partners. Under the Company’s fixed-fee agreements with Delta, United, Alaska, and American, 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 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, 2015, 2014 and 2013 were $504.9 million, $497.0 million and $500.2 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. 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, 2015, 2014 and 2013, 505,000 , 3,191,000 and 3,072,000 shares reserved for issuance upon the exercise of outstanding options were excluded from the computation of Diluted EPS respectively, as their inclusion would be anti ‑dilutive. 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, 2015, 2014 and 2013 (in thousands): Year Ended December 31, 2015 2014 2013 Numerator: Net Income (Loss) $ $ $ Denominator: Denominator for basic earnings per-share weighted average shares Dilution due to stock options and restricted stock — 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. Also, comprehensive income (loss) consisted of net income (loss) plus changes in unrealized appreciation (depreciation) on marketable securities and unrealized gain (loss) on foreign currency translation adjustment related to the Company’s equity investment in Trip Linhas Aereas, a regional airline operating in Brazil (“TRIP”) and Mekong Aviation Joint Stock Company, an airline operating in Vietnam (“Air Mekong”). 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, 2015. 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 $1,939.8 million as of December 31, 2015, as compared to the carrying amount of $1,948.8 millio n as of December 31, 2015. The Company’s fair value of long ‑term debt as of December 31, 2014 was $ 1,813.1 million as compared to the carrying amount o f $ 1,745.8 mill ion as of December 31, 2014. 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 Airline s and ExpressJet, as well as other activities. 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 to January 1, 2018. The FASB also proposed permitting early adoption of the standard, but not before January 1, 2017. Entities may use a full retrospective approach or report the cumulative effect as of the date of adoption. The Company’s management is currently evaluating the impact the adoption of ASU No. 2014-09 is anticipated to have on the Company’s consolidated financial statements. In April 2015, the FASB issued Accounting Standards Update No. 2015-03, “Simplifying the Presentation of Debt Issuance Costs” (“ASU No. 2015-03”). In August 2015, ASU No. 2015-03 was amended to modify existing guidance to require the presentation of debt issuance costs in the balance sheet as a deduction from the carrying amount of the related debt liability instead of as a deferred charge. It is effective for annual reporting periods beginning after December 15, 2015, but early adoption is permitted. The Company anticipates reclassifying the unamortized debt issuance costs and present debt net of those unamortized costs on its balance sheet upon adoption of ASU No. 2015-03. As of December 31, 2015, the Company had $20.9 million in unamortized debt issuance costs. 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”). The standard 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 is currently evaluating the impact the adoption of ASU No. 2015-17 is anticipated to have on the Company’s consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases (“ASU 2016-02”). The standard 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 2016-02 will be effective beginning in the first quarter of 2019. Early adoption of ASU 2016-02 is permitted. The new leases standard 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 of adopting ASU 2016-02 on the Company’s consolidated financial statements. Immaterial error correction to consolidated balance sheet In connection with the preparation of the Company’s consolidated financial statements for the year ended December 31, 2015, the Company determined that certain non-current prepaid aircraft rents previously reported were improperly presented as current on the Company’s consolidated balance sheet at December 31, 2014. As a result, current prepaid aircraft rents, as previously reported, were overstated by $201.5 million and non-current prepaid aircraft rents were understated by $201.5 million. The Company concluded that the error was not material to the consolidated balance sheet, but has elected to correct the error in the accompanying 2014 consolidated financial statements for consistency of presentation. The classification error had no effect on the consolidated statements of comprehensive income (loss), stockholders’ equity, or cash flows for the year ended December 31, 2014.

Segment Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2015
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 operating segments consist of the operations of SkyWest Airlines, ExpressJet and SkyWest Leasing activities. Corporate overhead expense incurred by the Company is allocated to the operating expenses of SkyWest Airlines and ExpressJet. During the fourth quarter of 2015, due to the increase in acquired E175 aircraft and the related aircraft debt financing, the Company’s chief operating decision maker started to analyze the flight operations of the Company’s E175 aircraft separately from the acquisition, ownership and financing costs and related revenue. Because of this change, the “ SkyWest Leasing ” segment includes revenue attributed to the Company’s E175 ownership cost earned under the applicable fixed-fee flying cont r act s , 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. As a result of the change in segmentation, prior periods have been recast to conform to the current presentation. The Company reclassified $15.0 million of operating revenue, $8.5 million of depreciation expense, $5.0 million of interest expense, $1.6 million of segment profit, $527.0 million of total assets and $535.5 million of capital expenditures (including non-cash) from the “SkyWest Airlines” segment to the “ SkyWest Leasing ” segment for the year ended December 31, 2014 to reflect the respective E175 activity in the “ SkyWest Leasing ” segment for 2014. During the fourth quarter of 2015, the Company resolved a contract matter with one of its major partners that resulted in a $7.9 million reduction to revenue. This reduction is reflected in the SkyWest Leasing segment as this amount related to an aircraft financing matter for the year ended December 31, 2015. The following represents the Company’s segment data for the years ended December 31, 2015, 2014 and 2013 (in thousands). 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 Interest expense Segment profit (loss) (1) Identifiable intangible assets, other than goodwill — — Total assets Capital expenditures (including non-cash) Year Ended December 31, 2013 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) — (1) Segment profit is operating income less interest expense

Long-term Debt

Long-term Debt	12 Months Ended
	Dec. 31, 2015
Long-term Debt
Long-term Debt	(3) Long ‑term Debt Long ‑term debt consisted of the following as of December 31, 2015 and 2014 (in thousands): December 31, December 31, 2015 2014 Notes payable to banks, due in semi-annual installments, variable interest based on LIBOR, or with interest rates ranging from 1.29% to 2.22% through 2016 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 1.76% 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 3.10% through 2019, secured by aircraft Notes payable to banks, due in quarterly installments plus interest at 3.39% to 4.02% through 2027, secured by aircraft Notes payable to banks, due in monthly installments, plus interest based on LIBOR at 3.21% to 3.33% 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 $ $ During the year ended December 31, 2015, the Company acquired 25 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, 2015, the Company had $1.9 billion of long ‑term debt obligations primarily related to the acquisition of CRJ200, CRJ700, CRJ900 and E175 aircraft. The average effective interest rate on the debt related to those long-term debt obligations was approximately 3.7% at December 31, 2015. 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, net of the write off of deferred loan costs associated with the debt, reflected as other income in the consolidated statements of comprehensive income (loss), of which the Company used $94 million in cash to pay off $128 million in debt, resulting in a pre-tax gain of $33 million during the fourth quarter of 2015. The aggregate amounts of principal maturities of long ‑term debt as of December 31, 2015 were as follows (in thousands): 2016 $ 2017 2018 2019 2020 Thereafter $ As of December 31, 2015 and 2014, SkyWest Airlines had a $25 million line of credit. As of December 31, 2015 and 2014, SkyWest Airlines had no amount outstanding under the facility. However, at December 31, 2015 and 2014 the Company had $6 million and $5 million, respectively, in letters of credit issued under the facility which reduced the amount available under the facility to $19 million and $20 million, respectively. The facility expires on April 19, 2016 and has a variable interest rate of Libor plus 3.0% . As of December 31, 2015 and 2014, the Company had $88.9 million and $79.9 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, 2015
Income Taxes
Income Taxes	(4) Income Taxes The provision for income taxes includes the following components (in thousands): Year ended December 31, 2015 2014 2013 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, 2015 2014 2013 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, 2015, the Company released a $0.9 m illion 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 gain resulting from the early retirement of certain long term debt which reduced the amount of deferred tax assets that were 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 allowance 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 additionally recorded a $2.0 m illion foreign tax expense associated with Brazilian withholding tax on the sale of the Company's equity ownership in TRIP. For the year ended December 31, 2013, the Company recorded a $1.4 million valuation allowance against certain deferred tax assets primarily associated with ExpressJet state net operating losses with a limited carry forward period. The valuation allowance was based on the Company’s assessment at December 31, 2013 of deferred tax assets that were anticipated to expire before the deferred tax assets may be utilized. 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, 2015 2014 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 US 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, 2015 and 2014, the Company had federal net operating losses, net of valuation allowance, of approximately $189.0 million and $379.3 million and state net operating losses of approximately $352.2 million and $452.2 million, respectively. The estimated effective tax rate applicable to the state and federal net operating losses net of valuation allowances as of December 31, 2015 was 35.0% and 2.6% , respectively. The Company anticipates that the federal and state net operating losses will start to expire in 2026 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, 2015 and 2014, the Company also had an alternative minimum tax credit of approximately $21.4 million and $17.6 million, respectively, which does not expire.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies
Commitments and Contingencies	(5) Commitments and Contingencies Lease Obligations The Company leases 470 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, 2015 (in thousands): Year ended December 31, 2016 $ 2017 2018 2019 2020 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, based on the current rules, the Company is not required to consolidate 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 11 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. During the year ended December 31, 2015, the Company built a maintenance facility in Boise, Idaho and entered into a sale lease-back agreement with the city of Boise. The sales price of the facility was $18.5 million and the operating lease expires in 2040. The future lease obligations for the Boise maintenance facility are included in the above future minimum rental payments schedule. Total rental expense for non-cancelable aircraft operating leases was approximately $273. 7 million, $305. 3 million and $325.4 million for the years ended December 31, 2015, 2014 and 2013, respectively. The minimum rental expense for airport station rents was approximately $35.1 million, $29.0 million and $35.1 million for the years ended December 31, 2015, 2014 and 2013, 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, 2015, 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 partners or customers but monitors the financial condition of its major partners. Under the majority of the Company’s code-share agreements, the Company receives weekly payments from its major code share partners that approximates 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 $187,300 and $326,600 as of December 31, 2015 and 2014, respectively. For the years ended December 31, 2015, 2014 and 2013, the Company’s contractual relationships with Delta and United combined accounted for approximately 86.9% , 88.7% and 91.6% , respectively of the Company’s total revenues. Employees Under Collective Bargaining Agreements As of December 31, 2015, the Company had approximately 18,300 full ‑time equivalent employees. Approximately 38.0% 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 Amendable Atlantic Southeast Flight Controllers Transport Workers Union of America Amendable Atlantic Southeast Mechanics International Brotherhood of Teamsters Amendable Atlantic Southeast Stock Clerks International Brotherhood of Teamsters Amendable ExpressJet Delaware Pilots Air Line Pilots Association International Amendable February 2018 ExpressJet Delaware Flight Attendants International Association of Machinists and Aerospace Workers Amendable ExpressJet Delaware Mechanics International Brotherhood of Teamsters Amendable ExpressJet Delaware Dispatchers Transport Workers Union of America Amendable ExpressJet Delaware Stock Clerks International Brotherhood of Teamsters Amendable In February 2016, the Atlantic Southeast Pilots and the ExpressJet Delaware Pilots ratified a two-year contract extension to their respective labor agreement s .

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2015
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 United States 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, 2015, 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, 2015 Total Level 1 Level 2 Level 3 Marketable Securities Bonds $ $ — $ $ — Commercial paper — — Asset backed securities $ $ — $ $ — Cash, Cash Equivalents and Restricted Cash — — Other Assets(a) (a) — — Total Assets Measured at Fair Value $ $ $ $ Fair Value Measurements as of December 31, 2014 Total Level 1 Level 2 Level 3 Marketable Securities Bonds $ $ — $ $ — Commercial paper — — Asset backed securities — — Cash, Cash Equivalents and Restricted Cash — — Other Assets(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 uses 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, 2015. 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, 2015 (in thousands): Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Auction Rate Securities Balance at January 1, 2015 $ Total realized and unrealized gains or (losses) Included in earnings — Included in other comprehensive income Transferred out — Settlements — Balance at December 31, 2015 $

Investment in Other Companies

Investment in Other Companies	12 Months Ended
	Dec. 31, 2015
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). In 2013, the Company sold its 30% ownership interest in Mekong Aviation Joint Stock Company, an airline operating in Vietnam (“Air Mekong”). The Company recognized a gain from the sale of its Air Mekong shares of $5 million during the year ended December 31, 2013, which is reflected in other income in the Consolidated Statements of Comprehensive Income (Loss). Additionally, in 2013, the Company terminated its sub ‑lease of certain aircraft to Air Mekong and recognized $5.1 million of other income during the year ended December 31, 2013 primarily due to the recognition of collected and realized contingent rent payments, net of the write ‑off of certain maintenance deposits.

Special Items

Special Items	12 Months Ended
	Dec. 31, 2015
Special Items
Special Items	(8) Special Items The following table summarizes the components of the Company's special items, for the year ended December 31, 2015, 2014 and 2013 (in thousands): Year ended December 31, 2015 2014 2013 Special items: EMB120 aircraft related items 1 $ — $ $ — ERJ145 aircraft related items 2 — — Paint facility and related items 3 — — Total special items $ — $ $ — (1) 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 write down of $48.3 million and accrued obligations on leased aircraft and related costs of $8.8 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. 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. (2) Consists 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. In November 2014, the Company entered into an amended and restated contract with United that accelerated the lease terminations of certain ERJ145 aircraft and accelerated the termination date of the Company’s flying contract to operate the ERJ145s with United from the year 2020 to 2017. The reduced term shortened the anticipated useful life of the ERJ145 long-lived assets which triggered the impairment evaluation. These special items are reflected in the ExpressJet operating expenses under Note 2 Segment Reporting . (3) 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, 2015
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. In prior years, the Company adopted three stock option plans: the Executive Stock Incentive Plan (the “Executive Plan”), the 2001 Allshare Stock Option Plan (the “Allshare Plan”) and SkyWest Inc. Long ‑Term Incentive Plan (the “2006 Incentive Plan”). As of December 31, 2015, options to purchase an aggregate 76,923 shares of the Company’s common stock remained outstanding under the Executive Plan, the Allshare Plan and the 2006 Incentive Plan. There are no additional shares of common stock available for issuance under these plans. 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 267,433 , 255,503 and 173,560 stock options to employees under the 2010 Incentive Plan during the years ended December 31, 2015, 2014 and 2013, respectively. Stock options granted in 2015 vest in three equal installments over a three-year period. Stock options granted in 2014 and 2013 have three-year vesting periods. The following table shows the assumptions used and weighted average fair value for grants in the years ended December 31, 2015, 2014 and 2013. 2015 2014 2013 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, 2015, the Company granted 408,163 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, 2015 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, 2015 was $13.57 per share. The following table summarizes the activity of restricted stock units granted to certain Company employees as of December 31, 2015, 2014 and 2013: Weighted-Average Grant-Date Fair Number of Shares Value Non-vested shares outstanding at December 31, 2012 $ Granted Vested Cancelled 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 During the year ended December 31, 2015, 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, 2017. 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, 2015. 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 $ During the years ended December 31, 2015, 2014 and 2013 the Company granted fully ‑vested shares of common stock to the Company’s directors in the amounts of 36,950 , 44,631 and 29,453 shares, respectively, with a weighted average grant ‑date fair value of $14.05 , $12.10 , and $13.24 , respectively . During the year ended December 31, 2015, 2014 and 2013, the Company recorded equity ‑based compensation expense of $5. 4 million, $5. 3 million and $4.4 million , respectively. As of December 31, 2015, the Company had $8.7 million of total unrecognized compensation cost related to non ‑vested stock options and non ‑vested restricted stock grants. 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 2.0 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, 2015, 2014 and 2013: 2015 2014 2013 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, 2015 years $ Exercisable at December 31, 2014 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, 2015, 2014 and 2013 was $1,800,000 , $30,000 and $172,000 , respectively. The following table summarizes the status of the Company’s non ‑vested stock options as of December 31, 2015: 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, 2015: 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 $18 years $8 to $18 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, 2015
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 $20.4 million, $19.3 million and $18.3 million for the years ended December 31, 2015, 2014 and 2013, 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. Effective December 31, 2002, ExpressJet Delaware adopted the ExpressJet Airlines, Inc. 401(k) Savings Plan (the “ExpressJet Retirement Plan”). Substantially all of ExpressJet Delaware’s domestic employees were covered by this plan at the time of the ExpressJet Combination. 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 $24.0 million, $27.2 million and $26.7 million for the years ended December 31, 2015, 2014 and 2013, 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, 2015, 2014 and 2013: Year ended December 31, 2015 2014 2013 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, 2015, 2014 and 2013.

Stock Repurchase

Stock Repurchase	12 Months Ended
	Dec. 31, 2015
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. During the years ended December 31, 2015, 2014 and 2013, the Company repurchased 1.3 million, 0.7 million, 0.8 million shares of common stock for approximately $18.7 million, $8.4 million and $11.7 million, respectively at a weighted average price per share of $14.98 , $12.54 and $14.40 , respectively. As of December 31, 2015, the Company’s Board of Directors has not authorized additional repurchases of the Company’s common stock.

Related-Party Transactions

Related-Party Transactions	12 Months Ended
	Dec. 31, 2015
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 accounts with Zions. Zions is an equity participant in leveraged leases on one CRJ200, two CRJ700 and four EMB120 aircraft leased by the Company’s subsidiaries. Zions also refinanced five CRJ200 and two CRJ700 aircraft in 2012 for terms of three to four 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, 2015 and 2014 was $65.0 million and $90.6 million, respectively. During the year ended December 31, 2015, the Company purchased $363,910 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, 2015
Quarterly Financial Data (Unaudited)
Quarterly Financial Data (Unaudited)	(13) Quarterly Financial Data (Unaudited) Unaudited summarized financial data by quarter for 2015 and 2014 is as follows (in thousands, except per share data): 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: Year ended December 31, 2014 First Second Third Fourth Quarter Quarter Quarter Quarter Year Operating revenues $ $ $ $ $ Operating income Net income (loss) Net income (loss) per common share: Basic Diluted Weighted average common shares: Basic: Diluted:

SCHEDULE II_VALUATION AND QUALI

SCHEDULE II—VALUATION AND QUALIFYING ACCOUNTS	12 Months Ended
	Dec. 31, 2015
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, 2015, 2014 and 2013 (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, 2015: Allowance for inventory obsolescence $ — $ Allowance for doubtful accounts receivable — $ Year ended December 31, 2014: Allowance for inventory obsolescence $ — $ Allowance for doubtful accounts receivable — — $ Year ended December 31, 2013: Allowance for inventory obsolescence $ — $ Allowance for doubtful accounts receivable — — —

Nature of Operations and Summ22

Nature of Operations and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2015
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 SkyWest, Inc. and its subsidiaries, including SkyWest Airlines and ExpressJet, 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, 2015, through the filing date of the Company’s annual report with the U.S. Securities and Exchange Commission.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America 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 classifie d $8. 2 million and $ 11.6 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, 2015 and 2014, respectively.
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, 2015 and 2014 was as follows (in thousands): 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 $ $ $ $ Gross unrealized Gross unrealized At December 31, 2014 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, 2015 (in thousands): Maturities Amount Year 2016 $ Years 2017 through 2020 As of December 31, 2015 and 2014, the Company had classified $286.7 million and $415.3 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 approximately $2.3 million and $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 and 2014, respectively (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 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, 2015 and 2014 was $13.9 million and $11.6 million, respectively. 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 and rotable spares 3 – 10 years 0 - 30 % Ground equipment 5 – 10 years % Office equipment 5 – 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, 2015, the Company had approximatel y $5. 6 billion of property and equipment and related assets. Additionally, as of December 31, 2015, the Company had approximately $10. 5 m illion 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, 2015 and 2014, the Company had $23.3 million and $21.0 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. The Company did not recognize any impairment charges of long lived assets during 2015 or 2013. 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 the EMB120 long-lived assets, ERJ145 long-lived assets, Saltillo, Mexico paint facility and related 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, 2015, 2014 and 2013, the Company capitalized interest costs of approximately $2.2 million, $1. 8 million, and $1.2 million, respectively.
Maintenance	Maintenance The Company operates under a FAA 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 E-175 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 Company used the “deferral method” of accounting for its EMB120 turboprop aircraft engine overhauls, wherein the overhaul costs were capitalized and depreciated to the next estimated overhaul event, or remaining lease term for leased aircraft, whichever was shorter. In 2015, the Company removed all of its EMB120 aircraft from service. 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, “contract flying” or “capacity purchase agreements”) with Delta, United, American and Alaska, the major airline 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 completion of flights 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 a Revenue Sharing Arrangement (referred to as a “revenue-sharing” or “pro rate” 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 pro rate flying agreements when each flight is completed based upon the portion of the pro rate 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. 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 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 following summarizes the significant provisions of each code share agreement the Company has with each major partner: Delta Connection Agreements Number of Pass through costs aircraft under Term / Termination or costs paid directly Agreement agreements Dates by major partner SkyWest Airlines • CRJ 200 - 48 • The contract is scheduled to expire on an individual aircraft basis commencing in 2016 • Fuel Delta Connection • CRJ 700 - 19 • The final aircraft is scheduled to expire in 2022 • Engine Maintenance Agreement (fixed-fee arrangement) • CRJ 900 - 36 • The average remaining term of the aircraft under contract is 3.8 years • Landing fees • Upon expiration, aircraft may be renewed or extended • Station Rents, Deice • Insurance ExpressJet Delta • CRJ 200 - 42 • The contract is scheduled to expire on an individual aircraft basis commencing in 2016 • Fuel Connection • CRJ 700 - 41 • The final aircraft is scheduled to expire in 2022 • Engine Maintenance Agreement (fixed-fee arrangement) • CRJ 900 - 28 • The average remaining term of the aircraft under contract is 3.7 years • Landing fees • Upon expiration, aircraft may be renewed or extended • Station Rents, Deice • Insurance SkyWest Airlines • CRJ 200 - 21 • Terminable with 30 days' notice • None Pro-rate Agreement (revenue-sharing agreement) United Express Agreements Pass through costs Number of or costs paid aircraft under Term / Termination directly by major Agreement agreements Dates partner SkyWest Airlines • CRJ 200 - 57 • The contract is scheduled to expire on an individual aircraft basis commencing in 2016 • Fuel United Express • CRJ 700 - 70 • The final aircraft is scheduled to expire in 2027 • Landing fees Agreements (fixed-fee • E175 - 40 • The average remaining term of the aircraft under contract is 4.3 years • Station Rents, Deice arrangement) • Upon expiration, aircraft may be renewed or extended • Insurance ExpressJet United ERJ • ERJ 135 - 5 • The contract is scheduled to expire on an individual aircraft basis commencing in 2016 • Fuel Agreement (fixed-fee arrangement) • ERJ 145 - 166 • The final aircraft is scheduled to expire in 2017 • Engine Maintenance • The average remaining term of the aircraft under contract is 1.9 years • Landing fees • Upon expiration, aircraft may be renewed or extended • Station Rents, Deice • Insurance SkyWest Airlines United • CRJ 200 - 26 • Terminable with 120 days' notice • None Express Pro-rate Agreement (revenue-sharing arrangement) Alaska Capacity Purchase Agreement Pass through costs Number of or costs paid aircraft under Term / Termination directly by major Agreement agreements Dates partner SkyWest Airlines • CRJ 700 - 9 • The contract is scheduled to expire on an individual aircraft basis commencing in 2016 • Fuel Alaska Agreement • E175 - 5 • The final aircraft is scheduled to expire in 2028 • Landing fees (fixed-fee arrangement) • Upon expiration, aircraft may be renewed or extended • Station Rents, Deice • Insurance American Agreement Pass through costs Number of or costs paid aircraft under Term / Termination directly by major Agreement agreements Dates partner SkyWest Airlines • CRJ 200 - 12 • Scheduled to expire in 2016 • Fuel American Agreement • Upon expiration, aircraft may be renewed or extended • Landing fees (fixed-fee agreement) • Station Rents, Deice • Insurance SkyWest Airlines • CRJ 200 - 5 • Terminable with 120 days' notice • None American Pro-rate Agreement (revenue- sharing agreement) ExpressJet American • CRJ 200 - 11 • Scheduled to expire in 2017 • Fuel Agreement (fixed-fee • ERJ 145 - 16 • Upon expiration, aircraft may be renewed or extended • Landing fees agreement) • Station Rents, Deice • Insurance ExpressJet American Pro-rate • CRJ 200 - 3 • Terminable with 120 days' notice • None Agreement (revenue-sharing agreement)
Other Revenue Items	As of December 31, 2015, the Company anticipate d placing an additional 25 E175 aircraft with United, ten additional E175 aircraft with Alaska and 19 E175 aircraft with Delta. The delivery dates for the new aircraft are expected to take place from January 2016 to June 2017. Under the Company’s f ixed- fee a rrangements, the major airline partners compensate the Company for its costs of owning or leasing the aircraft on a monthly basis. 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 ERJ Agreement and ExpressJet American ERJ145 Agreement, the major partner provides the aircraft to the Company for a nominal amount. 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 partners. Under the Company’s fixed-fee agreements with Delta, United, Alaska, and American, 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 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, 2015, 2014 and 2013 were $504.9 million, $497.0 million and $500.2 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.
Deferred Aircraft Credits	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, 2015, 2014 and 2013, 505,000 , 3,191,000 and 3,072,000 shares reserved for issuance upon the exercise of outstanding options were excluded from the computation of Diluted EPS respectively, as their inclusion would be anti ‑dilutive. 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, 2015, 2014 and 2013 (in thousands): Year Ended December 31, 2015 2014 2013 Numerator: Net Income (Loss) $ $ $ Denominator: Denominator for basic earnings per-share weighted average shares Dilution due to stock options and restricted stock — 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. Also, comprehensive income (loss) consisted of net income (loss) plus changes in unrealized appreciation (depreciation) on marketable securities and unrealized gain (loss) on foreign currency translation adjustment related to the Company’s equity investment in Trip Linhas Aereas, a regional airline operating in Brazil (“TRIP”) and Mekong Aviation Joint Stock Company, an airline operating in Vietnam (“Air Mekong”).
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, 2015. 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 $1,939.8 million as of December 31, 2015, as compared to the carrying amount of $1,948.8 millio n as of December 31, 2015. The Company’s fair value of long ‑term debt as of December 31, 2014 was $ 1,813.1 million as compared to the carrying amount o f $ 1,745.8 mill ion as of December 31, 2014.
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 Airline s and ExpressJet, as well as other activities. 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 to January 1, 2018. The FASB also proposed permitting early adoption of the standard, but not before January 1, 2017. Entities may use a full retrospective approach or report the cumulative effect as of the date of adoption. The Company’s management is currently evaluating the impact the adoption of ASU No. 2014-09 is anticipated to have on the Company’s consolidated financial statements. In April 2015, the FASB issued Accounting Standards Update No. 2015-03, “Simplifying the Presentation of Debt Issuance Costs” (“ASU No. 2015-03”). In August 2015, ASU No. 2015-03 was amended to modify existing guidance to require the presentation of debt issuance costs in the balance sheet as a deduction from the carrying amount of the related debt liability instead of as a deferred charge. It is effective for annual reporting periods beginning after December 15, 2015, but early adoption is permitted. The Company anticipates reclassifying the unamortized debt issuance costs and present debt net of those unamortized costs on its balance sheet upon adoption of ASU No. 2015-03. As of December 31, 2015, the Company had $20.9 million in unamortized debt issuance costs. 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”). The standard 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 is currently evaluating the impact the adoption of ASU No. 2015-17 is anticipated to have on the Company’s consolidated financial statements.
Immaterial error correction to consolidated balance sheet	Immaterial error correction to consolidated balance sheet In connection with the preparation of the Company’s consolidated financial statements for the year ended December 31, 2015, the Company determined that certain non-current prepaid aircraft rents previously reported were improperly presented as current on the Company’s consolidated balance sheet at December 31, 2014. As a result, current prepaid aircraft rents, as previously reported, were overstated by $201.5 million and non-current prepaid aircraft rents were understated by $201.5 million. The Company concluded that the error was not material to the consolidated balance sheet, but has elected to correct the error in the accompanying 2014 consolidated financial statements for consistency of presentation. The classification error had no effect on the consolidated statements of comprehensive income (loss), stockholders’ equity, or cash flows for the year ended December 31, 2014.

Nature of Operations and Summ23

Nature of Operations and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2015
Nature of operations and significant accounting policies summary
Schedule of details of aircraft and agreements with other airlines	As of December 31, 2015, the Company had a combined fleet of 702 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 *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 were held for sale.
Schedule of the Company's position in marketable securities	The Company’s position in marketable securities as of December 31, 2015 and 2014 was as follows (in thousands): 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 $ $ $ $ Gross unrealized Gross unrealized At December 31, 2014 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, 2015 (in thousands): Maturities Amount Year 2016 $ Years 2017 through 2020
Schedule of property and equipment	Assets Depreciable Life Residual Value New Aircraft 18 years % Used Aircraft and rotable spares 3 – 10 years 0 - 30 % Ground equipment 5 – 10 years % Office equipment 5 – 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, 2015 2014 2013 Numerator: Net Income (Loss) $ $ $ Denominator: Denominator for basic earnings per-share weighted average shares Dilution due to stock options and restricted stock — 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	Number of Pass through costs aircraft under Term / Termination or costs paid directly Agreement agreements Dates by major partner SkyWest Airlines • CRJ 200 - 48 • The contract is scheduled to expire on an individual aircraft basis commencing in 2016 • Fuel Delta Connection • CRJ 700 - 19 • The final aircraft is scheduled to expire in 2022 • Engine Maintenance Agreement (fixed-fee arrangement) • CRJ 900 - 36 • The average remaining term of the aircraft under contract is 3.8 years • Landing fees • Upon expiration, aircraft may be renewed or extended • Station Rents, Deice • Insurance ExpressJet Delta • CRJ 200 - 42 • The contract is scheduled to expire on an individual aircraft basis commencing in 2016 • Fuel Connection • CRJ 700 - 41 • The final aircraft is scheduled to expire in 2022 • Engine Maintenance Agreement (fixed-fee arrangement) • CRJ 900 - 28 • The average remaining term of the aircraft under contract is 3.7 years • Landing fees • Upon expiration, aircraft may be renewed or extended • Station Rents, Deice • Insurance SkyWest Airlines • CRJ 200 - 21 • Terminable with 30 days' notice • None Pro-rate Agreement (revenue-sharing agreement)
United Express Agreements
Nature of operations and significant accounting policies summary
Schedule of details of aircraft and agreements with other airlines	Pass through costs Number of or costs paid aircraft under Term / Termination directly by major Agreement agreements Dates partner SkyWest Airlines • CRJ 200 - 57 • The contract is scheduled to expire on an individual aircraft basis commencing in 2016 • Fuel United Express • CRJ 700 - 70 • The final aircraft is scheduled to expire in 2027 • Landing fees Agreements (fixed-fee • E175 - 40 • The average remaining term of the aircraft under contract is 4.3 years • Station Rents, Deice arrangement) • Upon expiration, aircraft may be renewed or extended • Insurance ExpressJet United ERJ • ERJ 135 - 5 • The contract is scheduled to expire on an individual aircraft basis commencing in 2016 • Fuel Agreement (fixed-fee arrangement) • ERJ 145 - 166 • The final aircraft is scheduled to expire in 2017 • Engine Maintenance • The average remaining term of the aircraft under contract is 1.9 years • Landing fees • Upon expiration, aircraft may be renewed or extended • Station Rents, Deice • Insurance SkyWest Airlines United • CRJ 200 - 26 • Terminable with 120 days' notice • None Express Pro-rate Agreement (revenue-sharing arrangement)
Alaska Capacity Purchase Agreement
Nature of operations and significant accounting policies summary
Schedule of details of aircraft and agreements with other airlines	Pass through costs Number of or costs paid aircraft under Term / Termination directly by major Agreement agreements Dates partner SkyWest Airlines • CRJ 700 - 9 • The contract is scheduled to expire on an individual aircraft basis commencing in 2016 • Fuel Alaska Agreement • E175 - 5 • The final aircraft is scheduled to expire in 2028 • Landing fees (fixed-fee arrangement) • Upon expiration, aircraft may be renewed or extended • Station Rents, Deice • Insurance
American Agreements
Nature of operations and significant accounting policies summary
Schedule of details of aircraft and agreements with other airlines	Pass through costs Number of or costs paid aircraft under Term / Termination directly by major Agreement agreements Dates partner SkyWest Airlines • CRJ 200 - 12 • Scheduled to expire in 2016 • Fuel American Agreement • Upon expiration, aircraft may be renewed or extended • Landing fees (fixed-fee agreement) • Station Rents, Deice • Insurance SkyWest Airlines • CRJ 200 - 5 • Terminable with 120 days' notice • None American Pro-rate Agreement (revenue- sharing agreement) ExpressJet American • CRJ 200 - 11 • Scheduled to expire in 2017 • Fuel Agreement (fixed-fee • ERJ 145 - 16 • Upon expiration, aircraft may be renewed or extended • Landing fees agreement) • Station Rents, Deice • Insurance ExpressJet American Pro-rate • CRJ 200 - 3 • Terminable with 120 days' notice • None Agreement (revenue-sharing agreement)

Segment Reporting (Tables)

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2015
Segment Reporting
Schedule of Company's segment data	The following represents the Company’s segment data for the years ended December 31, 2015, 2014 and 2013 (in thousands). 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 Interest expense Segment profit (loss) (1) Identifiable intangible assets, other than goodwill — — Total assets Capital expenditures (including non-cash) Year Ended December 31, 2013 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) — Segment profit is operating income less interest expense

Long-term Debt (Tables)

Long-term Debt (Tables)	12 Months Ended
	Dec. 31, 2015
Long-term Debt
Schedule of long-term debt	Long ‑term debt consisted of the following as of December 31, 2015 and 2014 (in thousands): December 31, December 31, 2015 2014 Notes payable to banks, due in semi-annual installments, variable interest based on LIBOR, or with interest rates ranging from 1.29% to 2.22% through 2016 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 1.76% 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 3.10% through 2019, secured by aircraft Notes payable to banks, due in quarterly installments plus interest at 3.39% to 4.02% through 2027, secured by aircraft Notes payable to banks, due in monthly installments, plus interest based on LIBOR at 3.21% to 3.33% 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 maturities of long-term debt	The aggregate amounts of principal maturities of long ‑term debt as of December 31, 2015 were as follows (in thousands): 2016 $ 2017 2018 2019 2020 Thereafter $

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2015
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, 2015 2014 2013 Current tax provision (benefit): Federal $ $ $ State Foreign — — Deferred tax provision (benefit): Federal State Provision for income taxes $ $ $
Schedule of income tax rate reconciliation	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, 2015 2014 2013 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, 2015 2014 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, 2015
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, 2015 (in thousands): Year ended December 31, 2016 $ 2017 2018 2019 2020 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 Amendable Atlantic Southeast Flight Controllers Transport Workers Union of America Amendable Atlantic Southeast Mechanics International Brotherhood of Teamsters Amendable Atlantic Southeast Stock Clerks International Brotherhood of Teamsters Amendable ExpressJet Delaware Pilots Air Line Pilots Association International Amendable February 2018 ExpressJet Delaware Flight Attendants International Association of Machinists and Aerospace Workers Amendable ExpressJet Delaware Mechanics International Brotherhood of Teamsters Amendable ExpressJet Delaware Dispatchers Transport Workers Union of America Amendable ExpressJet Delaware Stock Clerks International Brotherhood of Teamsters Amendable

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2015
Fair Value Measurements
Schedule of assets measured at fair value on a recurring basis	As of December 31, 2015, 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, 2015 Total Level 1 Level 2 Level 3 Marketable Securities Bonds $ $ — $ $ — Commercial paper — — Asset backed securities $ $ — $ $ — Cash, Cash Equivalents and Restricted Cash — — Other Assets(a) (a) — — Total Assets Measured at Fair Value $ $ $ $ Fair Value Measurements as of December 31, 2014 Total Level 1 Level 2 Level 3 Marketable Securities Bonds $ $ — $ $ — Commercial paper — — Asset backed securities — — Cash, Cash Equivalents and Restricted Cash — — Other Assets(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, 2015 (in thousands): Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Auction Rate Securities Balance at January 1, 2015 $ Total realized and unrealized gains or (losses) Included in earnings — Included in other comprehensive income Transferred out — Settlements — Balance at December 31, 2015 $

Special Items (Tables)

Special Items (Tables)	12 Months Ended
	Dec. 31, 2015
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, 2015, 2014 and 2013 (in thousands): Year ended December 31, 2015 2014 2013 Special items: EMB120 aircraft related items 1 $ — $ $ — ERJ145 aircraft related items 2 — — Paint facility and related items 3 — — Total special items $ — $ $ — (1) 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 write down of $48.3 million and accrued obligations on leased aircraft and related costs of $8.8 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. 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. (2) Consists 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. In November 2014, the Company entered into an amended and restated contract with United that accelerated the lease terminations of certain ERJ145 aircraft and accelerated the termination date of the Company’s flying contract to operate the ERJ145s with United from the year 2020 to 2017. The reduced term shortened the anticipated useful life of the ERJ145 long-lived assets which triggered the impairment evaluation. These special items are reflected in the ExpressJet operating expenses under Note 2 Segment Reporting . (3) 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, 2015
Schedule of assumptions used and weighted average fair value for stock option grants	2015 2014 2013 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	Weighted-Average Grant-Date Fair Number of Shares Value Non-vested shares outstanding at December 31, 2012 $ Granted Vested Cancelled 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
Schedule of stock option activity	2015 2014 2013 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, 2015 years $ Exercisable at December 31, 2014 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, 2015: 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, 2015: 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 $18 years $8 to $18 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, 2015. 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 $

Retirement Plans and Employee31

Retirement Plans and Employee Stock Purchase Plans (Tables)	12 Months Ended
	Dec. 31, 2015
Retirement Plans and Employee Stock Purchase Plans
Schedule of purchases made under the 2009 Employee Stock Purchase Plans	Year ended December 31, 2015 2014 2013 Number of shares purchased Average price of shares purchased $ $ $

Quarterly Financial Data (Una32

Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Data (Unaudited)
Schedule of Quarterly Financial Data (Unaudited)	Unaudited summarized financial data by quarter for 2015 and 2014 is as follows (in thousands, except per share data): 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: Year ended December 31, 2014 First Second Third Fourth Quarter Quarter Quarter Quarter Year Operating revenues $ $ $ $ $ Operating income Net income (loss) Net income (loss) per common share: Basic Diluted Weighted average common shares: Basic: Diluted:

Nature of Operations and Summ33

Nature of Operations and Summary of Significant Accounting Policies (Details)	12 Months Ended
	Dec. 31, 2015itemaircraft
Agreements with other airlines
Number of daily departures to different destinations | item	3,400
Number of aircrafts held by entity	702
United
Agreements with other airlines
Number of aircrafts held by entity	364
Percentage of aggregate capacity operated	57.50%
Delta
Agreements with other airlines
Number of aircrafts held by entity	235
Percentage of aggregate capacity operated	33.20%
American
Agreements with other airlines
Number of aircrafts held by entity	47
Percentage of aggregate capacity operated	6.40%
Alaska
Agreements with other airlines
Number of aircrafts held by entity	14
Percentage of aggregate capacity operated	2.90%
Aircraft in scheduled service
Agreements with other airlines
Number of aircrafts held by entity	660
Subleased to an un-affiliated entity
Agreements with other airlines
Number of aircrafts held by entity	2
Other
Agreements with other airlines
Number of aircrafts held by entity	40
CRJ 200
Agreements with other airlines
Number of aircrafts held by entity	237
CRJ 200 | United
Agreements with other airlines
Number of aircrafts held by entity	83
CRJ 200 | Delta
Agreements with other airlines
Number of aircrafts held by entity	111
CRJ 200 | American
Agreements with other airlines
Number of aircrafts held by entity	31
CRJ 200 | Aircraft in scheduled service
Agreements with other airlines
Number of aircrafts held by entity	225
CRJ 200 | Subleased to an un-affiliated entity
Agreements with other airlines
Number of aircrafts held by entity	2
CRJ 200 | Other
Agreements with other airlines
Number of aircrafts held by entity	10
CRJ 700
Agreements with other airlines
Number of aircrafts held by entity	139
CRJ 700 | United
Agreements with other airlines
Number of aircrafts held by entity	70
CRJ 700 | Delta
Agreements with other airlines
Number of aircrafts held by entity	60
CRJ 700 | Alaska
Agreements with other airlines
Number of aircrafts held by entity	9
CRJ 700 | Aircraft in scheduled service
Agreements with other airlines
Number of aircrafts held by entity	139
CRJ 900
Agreements with other airlines
Number of aircrafts held by entity	64
CRJ 900 | Delta
Agreements with other airlines
Number of aircrafts held by entity	64
CRJ 900 | Aircraft in scheduled service
Agreements with other airlines
Number of aircrafts held by entity	64
ERJ135
Agreements with other airlines
Number of aircrafts held by entity	9
ERJ135 | United
Agreements with other airlines
Number of aircrafts held by entity	5
ERJ135 | Aircraft in scheduled service
Agreements with other airlines
Number of aircrafts held by entity	5
ERJ135 | Other
Agreements with other airlines
Number of aircrafts held by entity	4
ERJ 145
Agreements with other airlines
Number of aircrafts held by entity	182
ERJ 145 | United
Agreements with other airlines
Number of aircrafts held by entity	166
ERJ 145 | American
Agreements with other airlines
Number of aircrafts held by entity	16
ERJ 145 | Aircraft in scheduled service
Agreements with other airlines
Number of aircrafts held by entity	182
E 175
Agreements with other airlines
Number of aircrafts held by entity	45
E 175 | United
Agreements with other airlines
Number of aircrafts held by entity	40
E 175 | Alaska
Agreements with other airlines
Number of aircrafts held by entity	5
E 175 | Aircraft in scheduled service
Agreements with other airlines
Number of aircrafts held by entity	45
EMB 120
Agreements with other airlines
Number of aircrafts held by entity	26
EMB 120 | Other
Agreements with other airlines
Number of aircrafts held by entity	26

Nature of Operations and Summ34

Nature of Operations and Summary of Significant Accounting Policies (Details 2) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Nature of Operations and Summary of Significant Accounting Policies
Restricted cash	$ 8,216	$ 11,582

Nature of Operations and Summ35

Nature of Operations and Summary of Significant Accounting Policies (Details 3) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Maturities of marketable securities
Year 2,016	$ 231,298
Years 2017 through 2020	55,370
Marketable securities	$ 286,700	$ 415,300
Maximum period for redemption	1 year
Investment as non-current	$ 2,300	2,300
Total cash and cash equivalents	203,035	132,275	$ 170,636	$ 133,772
Amortized Cost	286,887	415,726
Gross unrealized holding gains	1	12
Gross unrealized holding losses	(220)	(465)
Marketable securities	286,668	415,273
Total cash and cash equivalents and available for sale securities, amortized cost	489,922	548,001
Total cash and cash equivalents and available for sale securities, fair market value	489,703	547,548
Bonds and bond funds
Maturities of marketable securities
Amortized Cost	286,857	410,618
Gross unrealized holding gains		9
Gross unrealized holding losses	(220)	(464)
Marketable securities	286,637	410,163
Asset-backed Securities
Maturities of marketable securities
Amortized Cost	30	5,108
Gross unrealized holding gains	1	3
Gross unrealized holding losses		(1)
Marketable securities	$ 31	$ 5,110

Nature of Operations and Summ36

Nature of Operations and Summary of Significant Accounting Policies (Details 4) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Inventories
Inventory allowance	$ 13.9	$ 11.6

Nature of Operations and Summ37

Nature of Operations and Summary of Significant Accounting Policies (Details 5)	12 Months Ended
	Dec. 31, 2015
New aircraft
Property and Equipment
Depreciable Life	18 years
Residual Value (as a percent)	30.00%
Used Aircraft and rotable spares | Minimum
Property and Equipment
Depreciable Life	3 years
Residual Value (as a percent)	0.00%
Used Aircraft and rotable spares | Maximum
Property and Equipment
Depreciable Life	10 years
Residual Value (as a percent)	30.00%
Ground equipment
Property and Equipment
Residual Value (as a percent)	0.00%
Ground equipment | Minimum
Property and Equipment
Depreciable Life	5 years
Ground equipment | Maximum
Property and Equipment
Depreciable Life	10 years
Office Equipment
Property and Equipment
Residual Value (as a percent)	0.00%
Office Equipment | Minimum
Property and Equipment
Depreciable Life	5 years
Office Equipment | Maximum
Property and Equipment
Depreciable Life	7 years
Leasehold Improvements
Property and Equipment
Residual Value (as a percent)	0.00%
Leasehold Improvements | Minimum
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 (Details 6) - USD ($) $ in Thousands	Sep. 07, 2005	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Impairment of Long Lived and Intangible Assets
Property and equipment and related assets		$ 5,556,728	$ 4,923,563
Intangible assets		10,499	12,748	$ 14,998
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		$ 23,300	$ 21,000

Nature of Operations and Summ39

Nature of Operations and Summary of Significant Accounting Policies (Details 7) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Capitalized Interest
Capitalized interest costs	$ 2.2	$ 1.8	$ 1.2

Nature of Operations and Summ40

Nature of Operations and Summary of Significant Accounting Policies (Details 8) - aircraft	12 Months Ended	18 Months Ended
	Dec. 31, 2015	Jun. 30, 2017
Delta Connection Agreements | Forecast
Agreements with other airlines
Number of aircraft under contract		19
Delta Connection Agreements | ExpressJet
Agreements with other airlines
Term of agreement	3 years 8 months 12 days
Delta Connection Agreements | Sky West Airlines Inc
Agreements with other airlines
Term of agreement	3 years 9 months 18 days
Delta Connection Agreements | CRJ 200 | ExpressJet
Agreements with other airlines
Number of aircraft under contract	42
Delta Connection Agreements | CRJ 200 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract	48
Delta Connection Agreements | CRJ 700 | ExpressJet
Agreements with other airlines
Number of aircraft under contract	41
Delta Connection Agreements | CRJ 700 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract	19
Delta Connection Agreements | CRJ 900 | ExpressJet
Agreements with other airlines
Number of aircraft under contract	28
Delta Connection Agreements | CRJ 900 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract	36
United Express Agreements | Forecast
Agreements with other airlines
Number of aircraft under contract		25
United Express Agreements | ExpressJet
Agreements with other airlines
Term of agreement	1 year 10 months 24 days
United Express Agreements | Sky West Airlines Inc
Agreements with other airlines
Term of agreement	4 years 3 months 18 days
United Express Agreements | CRJ 200 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract	57
United Express Agreements | CRJ 700 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract	70
United Express Agreements | E 175 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract	40
United Express Agreements | ERJ135 | ExpressJet
Agreements with other airlines
Number of aircraft under contract	5
United Express Agreements | ERJ 145 | ExpressJet
Agreements with other airlines
Number of aircraft under contract	166
United Express Prorate Agreement | Sky West Airlines Inc
Agreements with other airlines
Notice period for termination of agreement	120 days
United Express Prorate Agreement | CRJ 200 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract	26
Alaska Capacity Purchase Agreement | Forecast
Agreements with other airlines
Number of aircraft under contract		10
Alaska Capacity Purchase Agreement | CRJ 700 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract	9
Alaska Capacity Purchase Agreement | E 175 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract	5
American Capacity Purchase Agreement | CRJ 200 | ExpressJet
Agreements with other airlines
Number of aircraft under contract	11
American Capacity Purchase Agreement | CRJ 200 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract	12
American Capacity Purchase Agreement | ERJ 145 | ExpressJet
Agreements with other airlines
Number of aircraft under contract	16
American Capacity Prorate Agreement | Sky West Airlines Inc
Agreements with other airlines
Notice period for termination of agreement	120 days
American Capacity Prorate Agreement | CRJ 200 | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract	5
Prorate Agreement | ExpressJet
Agreements with other airlines
Notice period for termination of agreement	120 days
Prorate Agreement | Sky West Airlines Inc
Agreements with other airlines
Number of aircraft under contract	21
Notice period for termination of agreement	30 days
Prorate Agreement | CRJ 200 | ExpressJet
Agreements with other airlines
Number of aircraft under contract	3

Nature of Operations and Summ41

Nature of Operations and Summary of Significant Accounting Policies (Details 9) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015USD ($)$ / sharesshares	Sep. 30, 2015USD ($)$ / sharesshares	Jun. 30, 2015USD ($)$ / sharesshares	Mar. 31, 2015USD ($)$ / sharesshares	Dec. 31, 2014USD ($)$ / sharesshares	Sep. 30, 2014USD ($)$ / sharesshares	Jun. 30, 2014USD ($)$ / sharesshares	Mar. 31, 2014USD ($)$ / sharesshares	Dec. 31, 2015USD ($)segment$ / sharesshares	Dec. 31, 2014USD ($)$ / sharesshares	Dec. 31, 2013USD ($)$ / sharesshares
Net Income (loss) Per Common Share
Number of outstanding options not included in computation of Diluted EPS (in shares) | shares									505,000	3,191,000	3,072,000
Numerator
Net Income (loss)	$ 40,454	$ 36,268	$ 31,475	$ 9,620	$ (27,868)	$ 41,338	$ (14,737)	$ (22,887)	$ 117,817	$ (24,154)	$ 58,956
Denominator
Denominator for basic earnings per-share weighted average shares | shares	50,880,000	50,616,000	51,357,000	51,457,000	51,174,000	51,127,000	51,183,000	51,467,000	51,077,000	51,237,000	51,688,000
Dilution due to stock options and restricted stock (in shares) | shares									748,000		734,000
Denominator for diluted earnings per-share weighted average shares | shares	51,657,000	51,282,000	51,971,000	52,392,000	51,174,000	52,036,000	51,183,000	51,467,000	51,825,000	51,237,000	52,422,000
Basic earnings per share (in dollars per share) | $ / shares	$ 0.80	$ 0.72	$ 0.61	$ 0.19	$ (0.54)	$ 0.81	$ (0.29)	$ (0.44)	$ 2.31	$ (0.47)	$ 1.14
Diluted earnings per share (in dollars per share) | $ / shares	$ 0.78	$ 0.71	$ 0.61	$ 0.18	$ (0.54)	$ 0.79	$ (0.29)	$ (0.44)	$ 2.27	$ (0.47)	$ 1.12
Other Revenue Items
Deemed rental income under code-share agreement									$ 504,900	$ 497,000	$ 500,200
Fair Value of Financial Instruments
Fair value of long-term debt	$ 1,939,800				$ 1,813,100				1,939,800	1,813,100
Carrying amount of long-term debt	1,948,803				$ 1,745,811				$ 1,948,803	$ 1,745,811
Segment Reporting
Operating segments number | segment									3
Recent Accounting Pronouncements
Unamortized debt issuance costs	$ 20,900								$ 20,900
Previously reported
Prior Period Adjustment [Abstract]
Overstatement of prepaid expense									201,500
Understatement of long term prepaid aircraft									$ 201,500

Segment Reporting (Details)

Segment Reporting (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015USD ($)	Sep. 30, 2015USD ($)	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Sep. 30, 2014USD ($)	Jun. 30, 2014USD ($)	Mar. 31, 2014USD ($)	Dec. 31, 2015USD ($)segmentaircraft	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Segment Reporting
Operating segments number | segment									3
Operating revenues	$ 752,744	$ 794,004	$ 788,417	$ 760,398	$ 813,854	$ 834,633	$ 816,574	$ 772,386	$ 3,095,563	$ 3,237,447	$ 3,297,725
Operating expense									2,861,048	3,212,599	3,144,614
Depreciation and amortization expense									264,507	259,642	245,005
Interest expense									75,850	65,995	68,658
Segment profit (loss)									158,665	(41,147)	84,453
Identifiable intangible assets, other than goodwill	10,499				12,748				10,499	12,748	14,998
Total assets	4,802,886				4,409,928				4,802,886	4,409,928	4,233,219
Capital expenditures (including non - cash)									$ 715,089	696,923	142,044
CRJ 200
Segment Reporting
Number of aircraft lease to third party | aircraft									2
SkyWest Airlines
Segment Reporting
Operating revenues									$ 1,848,363	1,873,675	1,827,568
Operating expense									1,630,200	1,758,145	1,644,129
Depreciation and amortization expense									141,189	162,699	155,667
Interest expense									36,141	39,452	43,920
Segment profit (loss)									182,022	76,078	139,519
Total assets	2,319,295				2,492,828				2,319,295	2,492,828	2,532,431
Capital expenditures (including non - cash)									30,897	137,678	103,387
SkyWest Airlines | E 175 | Restated Adjustment
Segment Reporting
Operating revenues										(15,000)
Depreciation and amortization expense										(8,500)
Interest expense										(5,000)
Segment profit (loss)										(1,600)
Total assets					(527,000)					(527,000)
Capital expenditures (including non - cash)										(535,500)
Express Jet Airlines Inc
Segment Reporting
Operating revenues									1,169,923	1,346,859	1,466,341
Operating expense									1,192,070	1,446,050	1,494,302
Depreciation and amortization expense									86,382	88,459	89,338
Interest expense									12,091	18,754	21,034
Segment profit (loss)									(34,238)	(117,945)	(48,995)
Identifiable intangible assets, other than goodwill	10,499				12,748				10,499	12,748	14,998
Total assets	1,332,995				1,390,129				1,332,995	1,390,129	1,700,788
Capital expenditures (including non - cash)									24,679	23,790	38,657
Other Segments
Segment Reporting
Operating revenues	(7,900)								77,277	16,913	3,816
Operating expense									38,778	8,404	6,183
Depreciation and amortization expense									36,936	8,484
Interest expense									27,618	7,789	3,704
Segment profit (loss)									10,881	720	$ (6,071)
Total assets	$ 1,150,596				526,971				1,150,596	526,971
Capital expenditures (including non - cash)									$ 659,513	535,455
Other Segments | E 175 | Restated Adjustment
Segment Reporting
Operating revenues										15,000
Depreciation and amortization expense										8,500
Interest expense										5,000
Segment profit (loss)										1,600
Total assets					$ 527,000					527,000
Capital expenditures (including non - cash)										$ 535,500

Long-term Debt (Details)

Long-term Debt (Details)	3 Months Ended	12 Months Ended
	Dec. 31, 2015USD ($)	Dec. 31, 2015USD ($)aircraft	Dec. 31, 2014USD ($)
Long-term Debt
Long-term debt	$ 1,948,803,000	$ 1,948,803,000	$ 1,745,811,000
Less current maturities	(272,027,000)	(272,027,000)	(211,821,000)
Long-term debt, net of current maturities	1,676,776,000	1,676,776,000	1,533,990,000
Aggregate amounts of principal maturities of long-term debt
2,016	272,027,000	272,027,000
2,017	248,629,000	248,629,000
2,018	230,681,000	230,681,000
2,019	223,898,000	223,898,000
2,020	183,620,000	183,620,000
Thereafter	789,948,000	789,948,000
Long-term debt	1,948,803,000	1,948,803,000	1,745,811,000
Repayment of debt in cash	94,000,000	110,800,000
TotalRepaymentOfDebt	128,000,000	145,400,000
Pre-tax gain	33,000,000	33,660,000
Letters of credit and surety bonds outstanding with various banks and surety institutions	88,900,000	88,900,000	79,900,000
CRJ
Long-term Debt
Long-term debt	$ 1,900,000,000	$ 1,900,000,000
Effective interest rate (as a percent)	3.70%	3.70%
Aggregate amounts of principal maturities of long-term debt
Long-term debt	$ 1,900,000,000	$ 1,900,000,000
E 175
Long-term Debt
Number of new aircraft acquired | aircraft		25
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 1.29% to 2.22% through 2016 to 2020, secured by aircraft
Long-term Debt
Interest rate, minimum (as a percent)		1.29%
Interest rate, maximum (as a percent)		2.22%
Long-term debt	108,348,000	$ 108,348,000	174,159,000
Aggregate amounts of principal maturities of long-term debt
Long-term debt	108,348,000	$ 108,348,000	174,159,000
Notes payable to a financing company, due in semi-annual installments, variable interest based on LIBOR, or with interest rates ranging from 1.76% to 3.25% through 2017 to 2021, secured by aircraft
Long-term Debt
Interest rate, minimum (as a percent)		1.76%
Interest rate, maximum (as a percent)		3.25%
Long-term debt	217,341,000	$ 217,341,000	350,177,000
Aggregate amounts of principal maturities of long-term debt
Long-term debt	217,341,000	$ 217,341,000	350,177,000
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
Interest rate, minimum (as a percent)		6.06%
Interest rate, maximum (as a percent)		6.51%
Long-term debt	108,069,000	$ 108,069,000	129,201,000
Aggregate amounts of principal maturities of long-term debt
Long-term debt	108,069,000	$ 108,069,000	129,201,000
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
Interest rate, minimum (as a percent)		5.78%
Interest rate, maximum (as a percent)		6.23%
Long-term debt	17,208,000	$ 17,208,000	25,090,000
Aggregate amounts of principal maturities of long-term debt
Long-term debt	17,208,000	$ 17,208,000	25,090,000
Notes payable to banks, due in monthly installments plus interest of 2.68% to 6.86% through 2025, secured by aircraft
Long-term Debt
Interest rate, minimum (as a percent)		2.68%
Interest rate, maximum (as a percent)		6.86%
Long-term debt	479,170,000	$ 479,170,000	572,446,000
Aggregate amounts of principal maturities of long-term debt
Long-term debt	$ 479,170,000	$ 479,170,000	572,446,000
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%	6.05%
Long-term debt	$ 11,304,000	$ 11,304,000	13,551,000
Aggregate amounts of principal maturities of long-term debt
Long-term debt	$ 11,304,000	$ 11,304,000	13,551,000
Notes payable to banks, due in monthly installments, plus interest at 3.10% through 2019, secured by aircraft
Long-term Debt
Interest rate (as a percent)	3.10%	3.10%
Long-term debt	$ 4,615,000	$ 4,615,000	5,909,000
Aggregate amounts of principal maturities of long-term debt
Long-term debt	4,615,000	$ 4,615,000	5,909,000
Notes payable to banks, due in quarterly installments plus interest at 3.39% to 4.02% through 2027, secured by aircraft(1)
Long-term Debt
Interest rate, minimum (as a percent)		3.39%
Interest rate, maximum (as a percent)		4.02%
Long-term debt	966,156,000	$ 966,156,000	446,724,000
Aggregate amounts of principal maturities of long-term debt
Long-term debt	966,156,000	$ 966,156,000	446,724,000
Notes payable to banks, due in monthly installments, plus interest based on LIBOR at 3.21% to 3.33% through 2017, secured by aircraft
Long-term Debt
Interest rate, minimum (as a percent)		3.21%
Interest rate, maximum (as a percent)		3.33%
Long-term debt	14,538,000	$ 14,538,000	28,554,000
Aggregate amounts of principal maturities of long-term debt
Long-term debt	14,538,000	$ 14,538,000	28,554,000
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, minimum (as a percent)		3.30%
Interest rate, maximum (as a percent)		2019.00%
Long-term debt	22,054,000	$ 22,054,000
Aggregate amounts of principal maturities of long-term debt
Long-term debt	$ 22,054,000	$ 22,054,000
Line of Credit | SkyWest Airlines
Long-term Debt
Interest rate (as a percent)	3.00%	3.00%
Aggregate amounts of principal maturities of long-term debt
Maximum borrowing capacity	$ 25,000,000	$ 25,000,000	25,000,000
Amount outstanding	0	0	0
Letters of credit	6,000,000	6,000,000	5,000,000
Line of credit facility, reduction of amount available	$ 19,000,000	$ 19,000,000	$ 20,000,000

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current tax provision (benefit):
Federal	$ 3,801	$ (176)	$ 1,767
State	1,035	838	343
Foreign		2,081
Total current payable	4,836	2,743	2,110
Deferred tax provision (benefit):
Federal	66,430	4,697	34,728
State	5,239	371	2,738
Total deferred payable	71,669	5,068	37,466
Provision for income taxes	$ 76,505	$ 7,811	$ 39,576

Income Taxes (Details 2)

Income Taxes (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
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 provision for income taxes
Computed provision (benefit) for income taxes at the statutory rate	$ 68,013	$ (5,720)	$ 34,486
State income tax provision (benefit), net of federal income tax benefit	5,416	(107)	2,867
Non-deductible expenses	3,641	3,865	3,257
Valuation allowance changes affecting the provision for income taxes	(899)	5,981	1,430
Foreign income taxes, net of federal & state benefit		1,973
Other, net	334	1,819	(2,464)
Provision for income taxes	76,505	7,811	$ 39,576
Deferred tax assets:
Intangible Asset	30,369	34,819
Accrued benefits	47,514	43,853
Net operating loss carryforward	82,211	152,361
AMT credit carryforward	21,391	17,590
Deferred aircraft credits	55,544	53,797
Accrued reserves and other	24,575	27,008
Total deferred tax assets	261,604	329,428
Valuation allowance	(8,126)	(9,025)
Deferred tax liabilities:
Accelerated depreciation	(902,322)	(895,405)
Total deferred tax liabilities	(902,322)	(895,405)
Net deferred tax liability	$ 648,844	$ 575,002

Income Taxes (Details 3)

Income Taxes (Details 3) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
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	$ 21,391	$ 17,590
Valuation allowance on acquired non-amortizable intangible tax assets and other tax assets	8,126	9,025
Domestic Tax Authority
Net operating losses
Operating loss carryforward	189,000	379,300
State
Net operating losses
Operating loss carryforward	$ 352,200	$ 452,200

Commitments and Contingencies47

Commitments and Contingencies (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)aircraft	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Commitments and Contingencies
Number of aircraft leased by the entity | aircraft	470
Future minimum rental payments required under operating leases
2,016	$ 269,520
2,017	192,122
2,018	154,077
2,019	121,107
2,020	133,659
Thereafter	349,038
Total future lease obligations	1,219,523
Rental expense for non-cancelable aircraft operating leases	273,696	$ 305,334	$ 325,360
Minimum rental expense for airport station rents	$ 35,100	$ 29,000	$ 35,100
Leveraged lease agreements term, maximum	11 years
Sale lease-back agreement, sales price of the facility	$ 18,500

Commitments and Contingencies48

Commitments and Contingencies (Details 2)	12 Months Ended
	Dec. 31, 2015USD ($)employee	Dec. 31, 2014USD ($)	Dec. 31, 2013
Concentration Risk and Significant Customers
Allowance for doubtful accounts | $	$ 187,300	$ 326,600
Number of full-time equivalent employees	18,300
Revenue from Rights Concentration Risk | Customer Concentration Risk | Delta, United, and Continental Combined
Concentration Risk and Significant Customers
Concentration risk (as a percent)	86.90%	88.70%	91.60%
Workforce Subject to Collective Bargaining Arrangements | Labor Force Concentration Risk
Concentration Risk and Significant Customers
Concentration risk (as a percent)	38.00%
Workforce Subject to Collective Bargaining Arrangements | Labor Force Concentration Risk | Atlantic Southeast Pilots
Concentration Risk and Significant Customers
Approximate Number of Active Employees	1,491
Workforce Subject to Collective Bargaining Arrangements | Labor Force Concentration Risk | Atlantic Southeast Flight Attendants
Concentration Risk and Significant Customers
Approximate Number of Active Employees	1,031
Workforce Subject to Collective Bargaining Arrangements | Labor Force Concentration Risk | Atlantic Southeast Flight Controllers
Concentration Risk and Significant Customers
Approximate Number of Active Employees	36
Workforce Subject to Collective Bargaining Arrangements | Labor Force Concentration Risk | Atlantic Southeast Mechanics
Concentration Risk and Significant Customers
Approximate Number of Active Employees	364
Workforce Subject to Collective Bargaining Arrangements | Labor Force Concentration Risk | Atlantic Southeast Stock Clerks
Concentration Risk and Significant Customers
Approximate Number of Active Employees	73
Workforce Subject to Collective Bargaining Arrangements | Labor Force Concentration Risk | ExpressJet Delaware Pilots
Concentration Risk and Significant Customers
Approximate Number of Active Employees	2,107
Workforce Subject to Collective Bargaining Arrangements | Labor Force Concentration Risk | ExpressJet Delaware Flight Attendants
Concentration Risk and Significant Customers
Approximate Number of Active Employees	993
Workforce Subject to Collective Bargaining Arrangements | Labor Force Concentration Risk | ExpressJet Delaware Mechanics
Concentration Risk and Significant Customers
Approximate Number of Active Employees	711
Workforce Subject to Collective Bargaining Arrangements | Labor Force Concentration Risk | ExpressJet Delaware Dispatchers
Concentration Risk and Significant Customers
Approximate Number of Active Employees	53
Workforce Subject to Collective Bargaining Arrangements | Labor Force Concentration Risk | ExpressJet Delaware Stock Clerks
Concentration Risk and Significant Customers
Approximate Number of Active Employees	96

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair Value Measurements
Marketable securities	$ 286,668	$ 415,273
Fair Value of Financial Instruments
Fair value of long-term debt	1,939,800	1,813,100
Carrying amount of long-term debt	1,948,803	1,745,811
Auction Rate Securities
Changes in assets measured at fair value on a recurring basis using significant unobservable inputs (level 3)
Balance at the beginning of the period	2,309
Total realized and unrealized gains or (losses) Included in other comprehensive income	12
Balance at the end of the period	2,321
Recurring | Fair value
Fair Value Measurements
Marketable securities	286,668
Cash, Cash Equivalents and Restricted Cash	211,251	143,857
Other Assets	2,321	2,309
Total Assets Measured at Fair Value	500,240	561,439
Recurring | Bonds and bond funds | Fair value
Fair Value Measurements
Marketable securities	286,637	410,163
Recurring | Asset-backed Securities | Fair value
Fair Value Measurements
Marketable securities	31	415,273
Recurring | Commercial Paper | Fair value
Fair Value Measurements
Marketable securities		5,110
Recurring | Level 1
Fair Value Measurements
Cash, Cash Equivalents and Restricted Cash	211,251	143,857
Total Assets Measured at Fair Value	211,251	143,857
Recurring | Level 2
Fair Value Measurements
Marketable securities	286,668
Total Assets Measured at Fair Value	286,668	415,273
Recurring | Level 2 | Bonds and bond funds
Fair Value Measurements
Marketable securities	286,637	410,163
Recurring | Level 2 | Asset-backed Securities
Fair Value Measurements
Marketable securities	31	415,273
Recurring | Level 2 | Commercial Paper
Fair Value Measurements
Marketable securities		5,110
Recurring | Level 3
Fair Value Measurements
Other Assets	2,321	2,309
Total Assets Measured at Fair Value	$ 2,321	$ 2,309

Investment in Other Companies (

Investment in Other Companies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Trip Linhas Aereas [Member]
Investments in other companies
Company's investment balance	$ 42
Gain (loss) on equity method investments	$ 24.9
Trip Linhas Aereas [Member] | Common Stock [Member]
Investments in other companies
Annual rate of return used to calculate the put option price (as a percent)	20.00%
Mekong Aviation Joint Stock Company [Member]
Investments in other companies
Percentage ownership acquired		30.00%
Gain on sale of cost method investment		$ 5
Other income recognized on termination of sub-lease with Air Mekong		$ 5.1

Special Items (Details)

Special Items (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Total Special items		$ 74,777
Aircraft rentals	$ 273,696	305,334	$ 325,360
Paint facility
Total Special items		4,800
EMB 120
Total Special items		57,046
Estimated fair value		48,300
Aircraft rentals		8,800
ERJ 145
Total Special items		12,931
Estimated fair value		11,400
Aircraft rentals		$ 1,500

Capital Transactions (Details)

Capital Transactions (Details) - shares	Dec. 31, 2015	Dec. 31, 2014
Preferred Stock
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock outstanding (in shares)	0

Capital Transactions (Details 2

Capital Transactions (Details 2)	May. 04, 2010shares	Dec. 31, 2015USD ($)$ / sharesshares	Dec. 31, 2014USD ($)$ / sharesshares	Dec. 31, 2013USD ($)$ / sharesshares	Dec. 31, 2015USD ($)plan$ / sharesshares	Dec. 31, 2014$ / sharesshares
Stock Compensation
Additional shares of common stock available for issuance					0
Compensation expenses
Stock based compensation expense | $		$ 5,368,000	$ 5,318,000	$ 4,363,000
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 | $					$ 8,700,000
Unrecognized compensation cost recognized over a weighted average period (in years)		2 years
Employee Stock Option
Stock Compensation
Options outstanding (in shares)		2,888,074	3,407,575	3,653,859	1,064,429	2,888,074
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)		1.18%	1.32%	1.21%
Risk-free interest rate (as a percent)		1.62%	1.50%	0.92%
Average expected life (years)		5 years 8 months 12 days	5 years 9 months 18 days	6 years
Expected volatility of common stock (as a percent)		0.401%	0.431%	0.446%
Forfeiture rate (as a percent)		0.00%	0.00%	0.00%
Weighted average fair value of option grants | $ / shares		$ 4.75	$ 4.47	$ 5.04
Weighted Average Grant-Date Fair Value
Granted (in dollars per share) | $ / shares		$ 4.92
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)		2,888,074	3,407,575	3,653,859
Granted (in shares)		267,433	255,503	173,560
Exercised (in shares)		(544,917)	(6,701)	(75,080)
Cancelled (in shares)		(1,546,161)	(768,303)	(344,764)
Outstanding at the end of the period (in shares)		1,064,429	2,888,074	3,407,575
Exercisable (in shares)					484,747	2,324,336
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share) | $ / shares		$ 16.46	$ 17.99	$ 18.44
Granted (in dollars per share) | $ / shares		13.63	11.96	13.24
Exercised (in dollars per share) | $ / shares		14.68	12.10	10.91
Cancelled (in dollars per share) | $ / shares		18.53	6.81	20.67
Outstanding at the end of the period (in dollars per share) | $ / shares		$ 13.64	$ 16.46	$ 17.99
Exercisable (in dollars per share) | $ / shares					$ 14.46	$ 17.39
Weighted Average Remaining Contractual Term
Outstanding, Weighted Average Remaining Contractual Term (in years)		3 years 8 months 12 days	1 year 8 months 12 days
Exercisable, Weighted Average Remaining Contractual Term (in years)		1 year 8 months 12 days	9 months 18 days
Aggregate Intrinsic Value
Average intrinsic value of shares outstanding | $					$ 5,726,700
Average intrinsic value of shares exercisable | $					$ 2,212,500
Total intrinsic value of options exercised | $		$ 1,800,000	$ 30,000	$ 172,000
Non-vested stock options
Non-vested shares at beginning of year (in shares)		563,738
Granted (in shares)		267,433	255,503	173,560
Vested (in shares)		(187,403)
Cancelled (in shares)		(64,086)
Non-vested shares at end of year (in shares)		579,682	563,738
Weighted Average Grant-Date Fair Value
Non-vested shares at beginning of year (in dollars per share) | $ / shares		$ 4.56
Weighted average fair value of option grants | $ / shares		4.75	$ 4.47	$ 5.04
Vested (in dollars per share) | $ / shares		4.43
Cancelled (in dollars per share) | $ / shares		4.65
Non-vested shares at end of year (in dollars per share) | $ / shares		$ 4.75	$ 4.56
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)		408,163	312,749	282,651
Number of shares
Nonvested shares at the beginning of the period (in shares)		723,176	733,591	698,885
Granted (in shares)		408,163	312,749	282,651
Vested (in shares)		(215,856)	(284,891)	(202,012)
Cancelled (in shares)		(106,184)	(38,273)	(45,933)
Nonvested shares at the end of the period (in shares)		809,299	723,176	733,591
Weighted Average Grant-Date Fair Value
Nonvested shares at the beginning of the period (in dollars per share) | $ / shares		$ 12.70	$ 13.79	$ 14.21
Granted (in dollars per share) | $ / shares		13.57	12	13.43
Vested (in dollars per share) | $ / shares		13.06	14.74	14.51
Cancelled (in dollars per share) | $ / shares		13.52	12.83	13.69
Nonvested shares at the end of the period (in dollars per share) | $ / shares		$ 13.13	$ 12.70	$ 13.79
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)		36,950	44,631	29,453
Number of shares
Granted (in shares)		36,950	44,631	29,453
Weighted Average Grant-Date Fair Value
Granted (in dollars per share) | $ / shares		$ 14.05	$ 12.10	$ 13.24
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)		222,583
Number of shares
Granted (in shares)		222,583
Cancelled (in shares)		(19,754)
Nonvested shares at the end of the period (in shares)		202,829
Weighted Average Grant-Date Fair Value
Granted (in dollars per share) | $ / shares		$ 13.61
Cancelled (in dollars per share) | $ / shares		13.51
Nonvested shares at the end of the period (in dollars per share) | $ / shares		$ 13.62
Group of Plans
Stock Compensation
Number of stock option plans | plan					3
Group of Plans | Employee Stock Option
Stock Compensation
Options outstanding (in shares)		76,923			76,923
Number of Options
Outstanding at the end of the period (in shares)		76,923
Long Term Incentive Plan 2010
Stock Compensation
Number of shares authorized	5,150,000
Long Term Incentive Plan 2010 | Employee Stock Option
Stock Compensation
Minimum incentive stock option exercise price, expressed as a percentage of common stock grant date market value	100.00%
Number of Options
Granted (in shares)		267,433	255,503	173,560
Non-vested stock options
Granted (in shares)		267,433	255,503	173,560
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)		408,163
Vesting period		3 years
Number of shares
Granted (in shares)		408,163
Weighted Average Grant-Date Fair Value
Granted (in dollars per share) | $ / shares		$ 13.57

Capital Transactions (Details 3

Capital Transactions (Details 3)	12 Months Ended
	Dec. 31, 2015$ / 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	5 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	859,595
Options outstanding, Weighted Average Remaining Contractual Life	4 years 1 month 6 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 13.31
Options Exercisable
Number of options Exercisable (in shares) | shares	305,331
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 13.90
$15 to $18
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)	$ 18
Options Outstanding
Number of options outstanding (in shares) | shares	185,376
Options outstanding, Weighted Average Remaining Contractual Life	1 year 4 months 24 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 15.43
Options Exercisable
Number of options Exercisable (in shares) | shares	179,416
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 15.64
$8 to $18
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)	$ 18
Options Outstanding
Number of options outstanding (in shares) | shares	1,064,429
Options outstanding, Weighted Average Remaining Contractual Life	3 years 8 months 12 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 13.64
Options Exercisable
Number of options Exercisable (in shares) | shares	484,747
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 14.46

Retirement Plans and Employee55

Retirement Plans and Employee Stock Purchase Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
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	$ 20.4	$ 19.3	$ 18.3
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	$ 24	$ 27.2	$ 26.7
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 Employee56

Retirement Plans and Employee Stock Purchase Plans (Details 2) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Retirement Plans and 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	254,098	295,035	299,786
Average price of shares purchased (in dollars per share)	$ 13.50	$ 12.72	$ 12.33

Stock Repurchase (Details)

Stock Repurchase (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Stock Repurchase
Common stock repurchased (in shares)	1.3	0.7	0.8
Common stock repurchased, value	$ 18.7	$ 8.4	$ 11.7
Weighted average price per share of common stock (in dollars per share)	$ 14.98	$ 12.54	$ 14.40

Related-Party Transactions (Det

Related-Party Transactions (Details)	12 Months Ended
	Dec. 31, 2015USD ($)aircraft	Dec. 31, 2012aircraft	Dec. 31, 2014USD ($)
Zions Bancorporation
Related Party Transactions
Cash balance with related party | $	$ 65,000,000		$ 90,600,000
Zions Bancorporation | Minimum
Related Party Transactions
Refinancing term		3 years
Zions Bancorporation | Maximum
Related Party Transactions
Refinancing term		4 years
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
Zions Bancorporation | Brasilia turboprop aircraft
Related Party Transactions
Equity participation in leveraged leases on number of aircraft	4
Affiliated Entity [Member] | ERJ 145
Related Party Transactions
Purchase from related party | $	$ 363,910

Quarterly Financial Data (Una59

Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Data (Unaudited)
Operating revenues	$ 752,744	$ 794,004	$ 788,417	$ 760,398	$ 813,854	$ 834,633	$ 816,574	$ 772,386	$ 3,095,563	$ 3,237,447	$ 3,297,725
Operating income	52,212	78,296	69,932	34,075	(19,702)	59,080	13,244	(27,774)	234,515	24,848	153,111
Net Income (loss)	$ 40,454	$ 36,268	$ 31,475	$ 9,620	$ (27,868)	$ 41,338	$ (14,737)	$ (22,887)	$ 117,817	$ (24,154)	$ 58,956
Net income (loss) per common share:
Basic (in dollars per share)	$ 0.80	$ 0.72	$ 0.61	$ 0.19	$ (0.54)	$ 0.81	$ (0.29)	$ (0.44)	$ 2.31	$ (0.47)	$ 1.14
Diluted (in dollars per share)	$ 0.78	$ 0.71	$ 0.61	$ 0.18	$ (0.54)	$ 0.79	$ (0.29)	$ (0.44)	$ 2.27	$ (0.47)	$ 1.12
Weighted average common shares:
Basic (in shares)	50,880	50,616	51,357	51,457	51,174	51,127	51,183	51,467	51,077	51,237	51,688
Diluted (in shares)	51,657	51,282	51,971	52,392	51,174	52,036	51,183	51,467	51,825	51,237	52,422

SCHEDULE II_VALUATION AND QUA60

SCHEDULE II—VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
VALUATION AND QUALIFYING ACCOUNTS
Balance at Beginning of Year	$ 11,914	$ 10,232	$ 9,283
Additions Charged to Costs and Expenses	2,345	1,682	949
Deductions	(139)
Balance at End of Year	14,120	11,914	10,232
Allowance for inventory obsolescence
VALUATION AND QUALIFYING ACCOUNTS
Balance at Beginning of Year	11,588	10,138	9,189
Additions Charged to Costs and Expenses	2,345	1,450	949
Balance at End of Year	13,933	11,588	10,138
Allowance for doubtful accounts receivable
VALUATION AND QUALIFYING ACCOUNTS
Balance at Beginning of Year	326	94	94
Additions Charged to Costs and Expenses		232
Deductions	(139)
Balance at End of Year	$ 187	$ 326	$ 94