Spirit Airlines (SAVEQ) 10-Q 4 May 22 2022 Q1 Quarterly report Financial data

Cover

Cover - shares	3 Months Ended
	Mar. 31, 2022	Apr. 29, 2022
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2022
Document Transition Report	false
Entity File Number	001-35186
Entity Registrant Name	SPIRIT AIRLINES, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	38-1747023
Entity Address, Address Line One	2800 Executive Way
Entity Address, City or Town	Miramar
Entity Address, State or Province	FL
Entity Address, Postal Zip Code	33025
City Area Code	954
Local Phone Number	447-7920
Title of 12(b) Security	Common Stock, $0.0001 par value
Security Exchange Name	NYSE
Trading Symbol	SAVE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		108,618,703
Amendment Flag	false
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001498710
Current Fiscal Year End Date	--12-31

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating revenues:
Total operating revenues	$ 967,315	$ 461,279
Operating expenses:
Salaries, wages and benefits	305,890	245,692
Aircraft fuel	368,585	142,930
Landing fees and other rents	82,936	72,108
Depreciation and amortization	76,191	74,312
Aircraft rent	66,044	54,782
Maintenance, materials and repairs	45,515	29,903
Distribution	35,351	23,642
Loss on disposal of assets	11,552	1,117
Special charges (credits)	15,563	(176,938)
Other operating	171,156	96,261
Total operating expenses	1,178,783	563,809
Operating income (loss)	(211,468)	(102,530)
Other (income) expense:
Interest expense	37,880	44,806
Capitalized interest	(5,262)	(4,732)
Interest income	(467)	(4,371)
Other (income) expense	417	(52)
Total other (income) expense	32,568	35,651
Income (loss) before income taxes	(244,036)	(138,181)
Provision (benefit) for income taxes	(49,333)	(25,860)
Net loss	$ (194,703)	$ (112,321)
Basic loss per share (in dollars per share)	$ (1.79)	$ (1.15)
Diluted loss per share (in dollars per share)	$ (1.79)	$ (1.15)
Passenger
Operating revenues:
Total operating revenues	$ 949,744	$ 450,335
Other
Operating revenues:
Total operating revenues	$ 17,571	$ 10,944

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Statement of Comprehensive Income [Abstract]
Net loss	$ (194,703)	$ (112,321)
Unrealized gain (loss) on short-term investment securities and cash and cash equivalents, net of deferred taxes of $(78) and $2	(267)	7
Interest rate derivative loss reclassified into earnings, net of taxes of $14 and $13	37	45
Other comprehensive income (loss)	(230)	52
Comprehensive loss	$ (194,933)	$ (112,269)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Statement of Comprehensive Income [Abstract]
Tax effect of the unrealized gain (loss) on short-term investment securities and cash and cash equivalents	$ (78)	$ 2
Interest rate derivative loss reclassified into earnings, tax	$ 14	$ 13

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 1,247,913	$ 1,333,507
Restricted cash	95,400	95,400
Short-term investment securities	106,013	106,313
Accounts receivable, net	160,672	128,828
Aircraft maintenance deposits, net	14,940	10,726
Income tax receivable	37,890	37,890
Prepaid expenses and other current assets	166,634	129,827
Total current assets	1,829,462	1,842,491
Property and equipment:
Flight equipment	4,382,247	4,356,523
Ground property and equipment	407,698	384,928
Less accumulated depreciation	(937,386)	(884,858)
Total property and equipment, net	3,852,559	3,856,593
Operating lease right-of-use assets	2,044,306	1,950,520
Pre-delivery deposits on flight equipment	489,214	484,821
Long-term aircraft maintenance deposits	34,796	38,166
Deferred heavy maintenance, net	324,282	330,062
Other long-term assets	37,098	37,372
Total assets	8,611,717	8,540,025
Current liabilities:
Accounts payable	47,422	44,952
Air traffic liability	558,303	382,317
Current maturities of long-term debt, net and finance leases	294,003	208,948
Current maturities of operating leases	164,814	158,631
Other current liabilities	546,733	480,754
Total current liabilities	1,611,275	1,275,602
Long-term debt, net and finance leases, less current maturities	2,801,759	2,975,823
Operating leases, less current maturities	1,835,306	1,751,351
Deferred income taxes	325,761	375,472
Deferred gains and other long-term liabilities	116,240	47,742
Shareholders’ equity:
Common stock	11	11
Additional paid-in-capital	1,135,872	1,131,826
Treasury stock, at cost	(77,411)	(75,639)
Retained earnings	863,666	1,058,369
Accumulated other comprehensive loss	(762)	(532)
Total shareholders’ equity	1,921,376	2,114,035
Total liabilities and shareholders’ equity	$ 8,611,717	$ 8,540,025

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2022	Mar. 31, 2021
Operating activities:
Net loss		$ (194,703)	$ (112,321)
Adjustments to reconcile net income (loss) to net cash provided by operations:
Losses reclassified from other comprehensive income		51	58
Share-based compensation		4,046	4,254
Allowance for doubtful accounts (recoveries)		0	(170)
Amortization of deferred gains, losses and debt issuance costs		3,421	3,509
Depreciation and amortization		76,191	74,312
Accretion of 8.00% senior secured notes		261	434
Amortization of debt discount		2,538	0
Deferred income tax expense (benefit)		(49,647)	(26,869)
Loss on disposal of assets		11,552	1,117
Changes in operating assets and liabilities:
Accounts receivable, net		(31,844)	(57,256)
Aircraft maintenance deposits, net		(844)	1,755
Long-term deposits and other assets		(35,339)	4,998
Prepaid income taxes		0	(303)
Deferred heavy maintenance, net		(17,698)	(10,466)
Income tax receivable		0	109,988
Accounts payable		(5,188)	3,202
Air traffic liability		175,986	107,206
Other liabilities		80,568	83,042
Other		194	158
Net cash provided by operating activities		19,545	186,648
Investing activities:
Purchase of available-for-sale investment securities		(26,749)	(20,692)
Proceeds from the maturity and sale of available-for-sale investment securities		26,500	20,500
Pre-delivery deposits on flight equipment, net of refunds		(5,858)	(52,738)
Capitalized interest		(4,172)	(4,342)
Assets under construction for others		0	(797)
Purchase of property and equipment		(47,340)	(39,437)
Net cash used in investing activities		(57,619)	(97,506)
Financing activities:
Proceeds from issuance of long-term debt		0	25,338
Proceeds from issuance of warrants		0	2,146
Payments on debt obligations		(44,338)	(135,925)
Payments on finance lease obligations		(210)	(189)
Reimbursement for assets under construction for others		0	586
Repurchase of common stock		(1,772)	(1,307)
Debt issuance costs		(1,200)	(2,444)
Net cash used by financing activities		(47,520)	(111,795)
Net increase (decrease) in cash, cash equivalents, and restricted cash		(85,594)	(22,653)
Cash, cash equivalents, and restricted cash at beginning of period	[1]	1,428,907	1,861,124
Cash, cash equivalents, and restricted cash at end of period	[1]	1,343,313	1,838,471
Cash payments for:
Interest, net of capitalized interest		25,781	40,206
Income taxes paid (received), net		303	(109,056)
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows for operating leases		67,089	61,378
Financing cash flows for finance leases		18	24
Non-cash transactions:
Capital expenditures funded by operating lease borrowings		$ 129,213	$ 82,745
[1]	(1) The sum of cash and cash equivalents and restricted cash on the Company's condensed consolidated balance sheets equals cash, cash equivalents, and restricted cash in our statement of cash flows.

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows (Parenthetical)	Mar. 31, 2022	Aug. 31, 2020
8.00% Senior Secured Notes Due 2025 | Secured Debt
Stated interest rate percentage	8.00%	8.00%

Condensed Consolidated Statem_6

Condensed Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-In-Capital	Additional Paid-In-CapitalCumulative Effect, Period of Adoption, Adjustment	Treasury Stock	Retained Earnings	Retained EarningsCumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2020	$ 2,249,695	$ (49,530)	$ 10	$ 799,549	$ (55,590)	$ (74,124)	$ 1,524,878	$ 6,060	$ (618)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	4,254			4,254
Repurchase of common stock	(1,307)					(1,307)
Changes in comprehensive income	52								52
Issuance of warrants	2,146			2,146
Net loss	(112,321)						(112,321)
Ending balance at Mar. 31, 2021	2,092,989		10	750,359		(75,431)	1,418,617		(566)
Beginning balance at Dec. 31, 2021	2,114,035		11	1,131,826		(75,639)	1,058,369		(532)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	4,046			4,046
Repurchase of common stock	(1,772)					(1,772)
Changes in comprehensive income	(230)								(230)
Net loss	(194,703)						(194,703)
Ending balance at Mar. 31, 2022	$ 1,921,376		$ 11	$ 1,135,872		$ (77,411)	$ 863,666		$ (762)

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements include the accounts of Spirit Airlines, Inc. (“Spirit”) and its consolidated subsidiaries (the "Company"). These unaudited condensed consolidated financial statements reflect all normal recurring adjustments which management believes are necessary to fairly present the financial position, results of operations and cash flows of the Company for the respective periods presented. Certain information and footnote disclosures normally included in the audited annual financial statements prepared in accordance with U.S. generally accepted accounting principles ("GAAP") have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission for Form 10-Q. These unaudited interim condensed consolidated financial statements should be read in conjunction with the audited financial statements of the Company and notes thereto included in the Company's Annual Report on Form 10-K for the year ended December 31, 2021 filed with the Securities and Exchange Commission on February 8, 2022. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect both 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 may differ from these estimates.

Merger

Merger	3 Months Ended
	Mar. 31, 2022
Business Combination and Asset Acquisition [Abstract]
Merger	Merger On February 5, 2022, Spirit Airlines entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Frontier Group Holdings, Inc., a Delaware corporation (“Frontier”), and Top Gun Acquisition Corp., a Delaware corporation and a direct, wholly owned subsidiary of Frontier (“Merger Sub”), pursuant to which and subject to the terms and conditions therein, Merger Sub will merge with and into Spirit Airlines, with Spirit Airlines continuing as the surviving entity (the “Merger”). As a result of the Merger, each existing share of Spirit Airlines’ common stock will be converted into the right to receive (i) $2.13 in cash, without interest and (ii) 1.9126 shares of Frontier’s common stock (“Frontier Common Stock”), par value $0.001 per share. Upon consummation of the Merger, existing shareholders of Spirit Airlines will own approximately 48.5% of the outstanding shares of Frontier on a fully diluted basis. Completion of the Merger is subject to the satisfaction or waiver of certain closing conditions, including, among other things, (1) approval of the Merger Agreement by Spirit Airlines’ stockholders, (2) receipt of applicable regulatory approvals, including approvals from the U.S. Federal Communications Commission (“FCC”), U.S. Federal Aviation Administration (“FAA”) and the U.S. Department of Transportation (“DOT”) and the expiration or early termination of the statutory waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and other required regulatory approvals; (3) the absence of any law or order prohibiting the consummation of the transactions; (4) the effectiveness of the registration statement to be filed by Frontier and Spirit Airlines with the SEC pursuant to the Merger Agreement; (5) the authorization and approval for listing on NASDAQ of the shares of Frontier Common Stock to be issued to holders of Spirit Airlines’ common stock in the Merger; and (6) the absence of any material adverse effect (as defined in the Merger Agreement) on either Spirit Airlines or Frontier. The Merger Agreement contains certain customary termination rights for Spirit Airlines and Frontier, including, without limitation, a right for either party to terminate if the Merger is not consummated on or before February 5, 2023, subject to certain extensions if needed to obtain regulatory approvals. Upon the termination of the Merger Agreement under specified circumstances, Spirit Airlines will be required to pay Frontier a breakup fee of $94.2 million. The Merger Agreement also provides the methodology by which certain expenses will be borne. On April 5, 2022, the Company announced that it received an unsolicited proposal from JetBlue Airways (JetBlue) to acquire all of the outstanding shares of Spirit Airlines’ common stock in an all-cash transaction for $33.00 per share. After consulting with financial and legal advisors, the Company's Board of Directors determined that JetBlue’s proposal could reasonably be likely to lead to a "Superior Proposal" as defined in the merger agreement with Frontier and evaluated the proposal in accordance with the terms of the merger agreement. On May 2, 2022, the Company announced that its Board of Directors, in consultation with outside financial and legal advisors, unanimously determined that the unsolicited proposal received from JetBlue does not constitute a "Superior Proposal" due to an unacceptable level of deal completion risk. The Company will continue to advance toward completing the transaction with Frontier, which is expected to close in the second half of 2022. The transaction is subject to customary closing conditions, including completion of the ongoing regulatory review process and approval of the Company's stockholders.

Revenue

Revenue	3 Months Ended
	Mar. 31, 2022
Revenue from Contract with Customer [Abstract]
Revenue	Revenue Operating revenues are comprised of passenger revenues, which includes fare and non-fare revenues, and other revenues. The following table shows disaggregated operating revenues for the three months ended March 31, 2022 and 2021. Three Months Ended March 31, 2022 2021 (in thousands) Operating revenues: Fare $ 418,418 $ 174,287 Non-fare 531,326 276,048 Total passenger revenues 949,744 450,335 Other 17,571 10,944 Total operating revenues $ 967,315 $ 461,279 The Company is managed as a single business unit that provides air transportation for passengers. Operating revenues by geographic region as defined by the Department of Transportation ("DOT") are summarized below: Three Months Ended March 31, 2022 2021 (in thousands) DOT—Domestic $ 827,054 $ 408,693 DOT—Latin America 140,261 52,586 Total $ 967,315 $ 461,279 The Company defers the amount for award travel obligations as part of loyalty deferred revenue within air traffic liability ("ATL") on the Company's condensed consolidated balance sheets and recognizes loyalty travel awards in passenger revenues as points are used for travel or expire unused. As of March 31, 2022 and December 31, 2021, the Company had ATL balances of $558.3 million and $382.3 million, respectively. Substantially all of the Company's ATL is expected to be recognized within 12 months of the respective balance sheet date. Loyalty Programs The Company operates the Spirit Saver$ Club ®

Loss on Disposal

Loss on Disposal	3 Months Ended
	Mar. 31, 2022
Discontinued Operations and Disposal Groups [Abstract]
Loss on Disposal	Loss on Disposal During the three months ended March 31, 2022, the Company recorded $11.6 million in loss on disposal of assets in the condensed consolidated st atement of operations. This loss on disposal primarily consisted of $6.6 million related to the impairment of one spare engine which was damaged beyond economic repair and $4.3 million related to the loss on three aircraft sale leaseback transactions completed during the first quarter of 2022. During the three months ended March 31, 2021, the Company recorded $1.1 million in loss on disposal of assets in the condensed consolidated statement of operations related to the sale of auxiliary power units ("APUs") and disposal of excess and obsolete inventory.

Special Charges (Credits)

Special Charges (Credits)	3 Months Ended
	Mar. 31, 2022
Special Credits [Abstract]
Special Charges (Credits)	Special Charges (Credits) During the three months ended March 31, 2022, the Company recorded $11.1 million within special charges (credits) on the Company's condensed consolidated statements of operations, in legal, advisory and other fees related to the Merger Agreement with Frontier executed during the first quarter of 2022. In addition, as part of the Merger Agreement, the Company implemented an employee retention bonus program. The target retention bonus will be paid to the Company's employees upon the successful close of the merger. In the event the merger fails or is abandoned, 50% of the target retention bonus will be paid to the Company's employees at the termination date of the merger. During the three months ended March 31, 2022, the Company recorded $4.5 million within special charges (credits) on the Company's condensed consolidated statements of operations, related to the Company's retention bonus program. During the three months ended March 31, 2021, the Company recorded $156.5 million, net of related costs, within special credits on the Company’s condensed consolidated statements of operations related to the grant component of the PSP2 agreement with the Treasury. These funds were used exclusively to pay for salaries, wages and benefits for the Company's Team Members through March 31, 2021. In addition, during the three months ended March 31, 2021, the Company recorded $21.3 million related to the CARES Act Employee Retention credit within special credits on the Company’s condensed consolidated statements of operation. These special credits were partially offset by $0.8 million in special charges recorded during the three months ended March 31, 2021. The $0.8 million was related to salaries, wages and benefits paid to rehired employees, previously terminated with the Company's involuntary employee separation program, in compliance with the restrictions of PSP2.

Loss per Share

Loss per Share	3 Months Ended
	Mar. 31, 2022
Earnings Per Share [Abstract]
Loss per Share	Loss per Share The following table sets forth the computation of basic and diluted loss per common share: Three Months Ended March 31, 2022 2021 (in thousands, except per-share amounts) Numerator Net loss $ (194,703) $ (112,321) Denominator Weighted-average shares outstanding, basic 108,581 97,775 Effect of dilutive shares — — Adjusted weighted-average shares outstanding, diluted 108,581 97,775 Loss per share Basic loss per common share $ (1.79) $ (1.15) Diluted loss per common share $ (1.79) $ (1.15)

Short-term Investment Securitie

Short-term Investment Securities	3 Months Ended
	Mar. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Short-term Investment Securities	Short-term Investment SecuritiesThe Company's short-term investment securities are classified as available-for-sale and generally consist of U.S. Treasury and U.S. government agency securities with contractual maturities of 12 months or less. These securities are stated at fair value within current assets on the Company's condensed consolidated balance sheets. Realized gains and losses on sales of investments, if any, are reflected in non-operating income (expense) in the condensed consolidated statements of operations. As of March 31, 2022 and December 31, 2021, the Company had $106.0 million and $106.3 million in short-term available-for-sale investment securities, respectively. During the three months ended March 31, 2022, these investments earned interest income at a weighted-average fixed rate of approximately 0.2%. For the three months ended March 31, 2022, an unrealized loss of $262 thousand, net of deferred taxes of $77 thousand, was recorded within accumulated other comprehensive income ("AOCI") related to these investment securities. For the three months ended March 31, 2021, an unrealized gain of $7 thousand, net o f deferred taxes of $2 thousand was recorded within AOCI related to these investment securities. For the three months ended March 31, 2022 and March 31, 2021, the Company had no realized gains or losses as the Company did not sell any of these securities during these periods. A s of March 31, 2022 and December 31, 2021, $305 thousand and

Accrued Liabilities

Accrued Liabilities	3 Months Ended
	Mar. 31, 2022
Payables and Accruals [Abstract]
Accrued Liabilities	Accrued Liabilities Other current liabilities as of March 31, 2022 and December 31, 2021 consist of the following: March 31, 2022 December 31, 2021 (in thousands) Salaries, wages and benefits $ 140,017 $ 142,893 Federal excise and other passenger taxes and fees payable 122,107 77,409 Airport obligations 94,505 85,772 Fuel 62,355 55,103 Aircraft maintenance 46,768 39,178 Interest payable 26,080 24,526 Aircraft and facility lease obligations 18,240 23,049 Other 36,661 32,824 Other current liabilities $ 546,733 $ 480,754

Leases

Leases	3 Months Ended
	Mar. 31, 2022
Leases [Abstract]
Leases	Leases The Company leases aircraft, engines, airport terminals, maintenance and training facilities, aircraft hangars, commercial real estate, and office and computer equipment, among other items. Certain of these leases include provisions for variable lease payments which are based on several factors, including, but not limited to, relative leased square footage, enplaned passengers, and airports’ annual operating budgets. Due to the variable nature of the rates, these leases are not recorded on the Company's condensed consolidated balance sheets as a right-of-use asset and lease liability. Lease terms are generally 8 years to 18 years for aircraft and up to 99 years for other leased equipment and property. During the three months ended March 31, 2022, the Company took delivery of three aircraft under sale leaseback transactions and one spare engine purchased with cash. As of March 31, 2022, the Company had a fleet consisting of 176 A320 family aircraft. As of March 31, 2022, the Company had 70 aircraft financed under operating leases with lease term expirations between 2023 and 2040. In addition, the Company owned 105 aircraft of which 33 were purchased off lease and were unencumbered as of March 31, 2022. The Company also had one aircraft recorded as a failed sale leaseback. The related finance obligation is recorded within long-term debt in the Company's condensed consolidated balance sheets. Refer to Note 12, Debt and Other Obligations for additional information. The related asset is recorded within flight equipment in the Company's condensed consolidated balance sheets. As of March 31, 2022, the Company also had 12 spare engines financed under operating leases with lease term expiration dates ranging from 2022 to 2033 and owned 21 spare engines, all of which, as of March 31, 2022, were pledged as collateral under the Company's revolving credit facility maturing in 2024. Some of the Company’s aircraft and engine master lease agreements provide that the Company pays maintenance reserves to aircraft lessors to be held as collateral in advance of the Company’s required performance of major maintenance activities. A majority of these maintenance reserve payments are calculated based on a utilization measure, such as flight hours or cycles, while some maintenance reserve payments are fixed, time-based contractual amounts. Maintenance reserve payments that are probable of being recovered when the Company performs qualifying maintenance are recorded in aircraft maintenance deposits on the Company's condensed consolidated balance sheets. Fixed maintenance reserve payments that are not probable of being recovered are considered lease payments and are included in the right-of-use asset and lease liability. Maintenance reserve payments that are based on a utilization measure and are not probable of being recovered are considered variable lease payments that are recognized when they are probable of being incurred and are not included in the right-of-use asset and lease liability. Some of the master lease agreements do not require that the Company pay maintenance reserves so long as the Company's cash balance does not fall below a certain level. As of March 31, 2022, the Company was in full compliance with those requirements and does not anticipate having to pay reserves related to these master leases in the future. Aircraft rent expense consists of monthly lease rents for aircraft and spare engines under the terms of the Company's aircraft and spare engine lease agreements recognized on a straight-line basis. Aircraft rent expense also includes maintenance reserves paid to aircraft lessors in advance of the performance of major maintenance activities that are not probable of being reimbursed and probable lease return condition obligations. Under the terms of the lease agreements, the Company will continue to operate and maintain the aircraft. Payments under the majority of the lease agreements are fixed for the term of the lease. The lease agreements contain standard termination events, including termination upon a breach of the Company's obligations to make rental payments and upon any other material breach of the Company's obligations under the leases, and standard maintenance and return condition provisions. These return provisions are evaluated at inception of the lease and throughout the lease terms and are accounted for as either fixed or variable lease payments (depending on the nature of the lease return condition) when it is probable that such amounts will be incurred. When determining probability and estimated cost of lease return obligations, there are various other factors that need to be considered such as the contractual terms of the lease, the ability to swap engines or other aircraft components, current condition of the aircraft, the age of the aircraft at lease expiration, utilization of engines and other components, the extent of repairs needed at return, return locations, current configuration of the aircraft and cost of repairs and materials at the time of return. Management assesses the factors listed above and the need to accrue lease return costs throughout the lease as facts and circumstances warrant an assessment. The Company expects lease return costs and unrecoverable maintenance deposits will increase as individual aircraft lease agreements approach their respective termination dates and the Company begins to accrue the estimated cost of return conditions for the corresponding aircraft. Upon a termination of the lease due to a breach by the Company, the Company would be liable for standard contractual damages, possibly including damages suffered by the lessor in connection with remarketing the aircraft or while the aircraft is not leased to another party. As of March 31, 2022, the Company's finance lease obligations primarily relate to the lease of computer equipment used by the Company's flight crew and office equipment. Payments under these finance lease agreements are fixed for terms ranging from 4 to 5 years. Finance lease assets are recorded within property and equipment and the related liabilities are recorded within long-term debt and finance leases in the Company's condensed consolidated balance sheets. During the fourth quarter of 2019, the Company purchased an 8.5-acre parcel of land for $41.0 million and entered into a 99-year lease agreement for the lease of a 2.6-acre parcel of land, in Dania Beach, Florida, where the Company is building its new headquarters campus. During January 2022, the Company began building its new headquarters campus with an expected completion during the fourth quarter 2023. In connection with the lease agreement, the Company is also expected to build a 200-unit residential building. The 8.5-acre parcel of land is capitalized within ground property and equipment on the Company's condensed consolidated balance sheets. The 99-year lease was determined to be an operating lease and is recorded within operating lease right-of-use asset and operating lease liability on the Company's condensed consolidated balance sheets. Operating lease commitments related to this lease are included in the table below within property facility leases. The following table provides details of the Company's future minimum lease payments under finance lease liabilities and operating lease liabilities recorded on the Company's condensed consolidated balance sheets as of March 31, 2022. The table does not include commitments that are contingent on events or other factors that are currently uncertain or unknown. Finance Leases Operating Leases Aircraft and Spare Engine Leases Property Facility Leases Other Total (in thousands) Remainder of 2022 $ 631 $ 199,747 $ 4,153 $ 118 $ 204,649 2023 465 260,628 5,548 13 266,654 2024 215 248,019 3,810 — 252,044 2025 117 229,777 1,192 — 231,086 2026 39 203,517 964 — 204,520 2027 and thereafter — 1,660,329 142,174 — 1,802,503 Total minimum lease payments $ 1,467 $ 2,802,017 $ 157,841 $ 131 $ 2,961,456 Less amount representing interest 72 826,808 133,060 1 959,941 Present value of minimum lease payments $ 1,395 $ 1,975,209 $ 24,781 $ 130 $ 2,001,515 Less current portion 761 160,378 4,306 130 165,575 Long-term portion $ 634 $ 1,814,831 $ 20,475 $ — $ 1,835,940 Commitments related to the Company's noncancellable short-term operating leases not recorded on the Company's condensed consolidated balance sheets are expected to be $4.5 million for the remainder of 2022 and none for 2023 and beyond. The table below presents information for lease costs related to the Company's finance and operating leases: Three Months Ended March 31, 2022 2021 (in thousands) Finance lease cost Amortization of leased assets $ 188 $ 168 Interest of lease liabilities 18 24 Operating lease cost Operating lease cost (1) 63,251 52,141 Short-term lease cost (1) 10,257 7,015 Variable lease cost (1) 48,694 38,149 Total lease cost $ 122,408 $ 97,497 (1) Expenses are classified within aircraft rent and landing fees and other rents on the Company's condensed consolidated statements of operations. The table below presents lease terms and discount rates related to the Company's finance and operating leases: March 31, 2022 March 31, 2021 Weighted-average remaining lease term Operating leases 14.0 years 13.2 years Finance leases 2.3 years 2.4 years Weighted-average discount rate Operating leases 5.62 % 6.06 % Finance leases 4.71 % 5.52 %
Leases	Leases The Company leases aircraft, engines, airport terminals, maintenance and training facilities, aircraft hangars, commercial real estate, and office and computer equipment, among other items. Certain of these leases include provisions for variable lease payments which are based on several factors, including, but not limited to, relative leased square footage, enplaned passengers, and airports’ annual operating budgets. Due to the variable nature of the rates, these leases are not recorded on the Company's condensed consolidated balance sheets as a right-of-use asset and lease liability. Lease terms are generally 8 years to 18 years for aircraft and up to 99 years for other leased equipment and property. During the three months ended March 31, 2022, the Company took delivery of three aircraft under sale leaseback transactions and one spare engine purchased with cash. As of March 31, 2022, the Company had a fleet consisting of 176 A320 family aircraft. As of March 31, 2022, the Company had 70 aircraft financed under operating leases with lease term expirations between 2023 and 2040. In addition, the Company owned 105 aircraft of which 33 were purchased off lease and were unencumbered as of March 31, 2022. The Company also had one aircraft recorded as a failed sale leaseback. The related finance obligation is recorded within long-term debt in the Company's condensed consolidated balance sheets. Refer to Note 12, Debt and Other Obligations for additional information. The related asset is recorded within flight equipment in the Company's condensed consolidated balance sheets. As of March 31, 2022, the Company also had 12 spare engines financed under operating leases with lease term expiration dates ranging from 2022 to 2033 and owned 21 spare engines, all of which, as of March 31, 2022, were pledged as collateral under the Company's revolving credit facility maturing in 2024. Some of the Company’s aircraft and engine master lease agreements provide that the Company pays maintenance reserves to aircraft lessors to be held as collateral in advance of the Company’s required performance of major maintenance activities. A majority of these maintenance reserve payments are calculated based on a utilization measure, such as flight hours or cycles, while some maintenance reserve payments are fixed, time-based contractual amounts. Maintenance reserve payments that are probable of being recovered when the Company performs qualifying maintenance are recorded in aircraft maintenance deposits on the Company's condensed consolidated balance sheets. Fixed maintenance reserve payments that are not probable of being recovered are considered lease payments and are included in the right-of-use asset and lease liability. Maintenance reserve payments that are based on a utilization measure and are not probable of being recovered are considered variable lease payments that are recognized when they are probable of being incurred and are not included in the right-of-use asset and lease liability. Some of the master lease agreements do not require that the Company pay maintenance reserves so long as the Company's cash balance does not fall below a certain level. As of March 31, 2022, the Company was in full compliance with those requirements and does not anticipate having to pay reserves related to these master leases in the future. Aircraft rent expense consists of monthly lease rents for aircraft and spare engines under the terms of the Company's aircraft and spare engine lease agreements recognized on a straight-line basis. Aircraft rent expense also includes maintenance reserves paid to aircraft lessors in advance of the performance of major maintenance activities that are not probable of being reimbursed and probable lease return condition obligations. Under the terms of the lease agreements, the Company will continue to operate and maintain the aircraft. Payments under the majority of the lease agreements are fixed for the term of the lease. The lease agreements contain standard termination events, including termination upon a breach of the Company's obligations to make rental payments and upon any other material breach of the Company's obligations under the leases, and standard maintenance and return condition provisions. These return provisions are evaluated at inception of the lease and throughout the lease terms and are accounted for as either fixed or variable lease payments (depending on the nature of the lease return condition) when it is probable that such amounts will be incurred. When determining probability and estimated cost of lease return obligations, there are various other factors that need to be considered such as the contractual terms of the lease, the ability to swap engines or other aircraft components, current condition of the aircraft, the age of the aircraft at lease expiration, utilization of engines and other components, the extent of repairs needed at return, return locations, current configuration of the aircraft and cost of repairs and materials at the time of return. Management assesses the factors listed above and the need to accrue lease return costs throughout the lease as facts and circumstances warrant an assessment. The Company expects lease return costs and unrecoverable maintenance deposits will increase as individual aircraft lease agreements approach their respective termination dates and the Company begins to accrue the estimated cost of return conditions for the corresponding aircraft. Upon a termination of the lease due to a breach by the Company, the Company would be liable for standard contractual damages, possibly including damages suffered by the lessor in connection with remarketing the aircraft or while the aircraft is not leased to another party. As of March 31, 2022, the Company's finance lease obligations primarily relate to the lease of computer equipment used by the Company's flight crew and office equipment. Payments under these finance lease agreements are fixed for terms ranging from 4 to 5 years. Finance lease assets are recorded within property and equipment and the related liabilities are recorded within long-term debt and finance leases in the Company's condensed consolidated balance sheets. During the fourth quarter of 2019, the Company purchased an 8.5-acre parcel of land for $41.0 million and entered into a 99-year lease agreement for the lease of a 2.6-acre parcel of land, in Dania Beach, Florida, where the Company is building its new headquarters campus. During January 2022, the Company began building its new headquarters campus with an expected completion during the fourth quarter 2023. In connection with the lease agreement, the Company is also expected to build a 200-unit residential building. The 8.5-acre parcel of land is capitalized within ground property and equipment on the Company's condensed consolidated balance sheets. The 99-year lease was determined to be an operating lease and is recorded within operating lease right-of-use asset and operating lease liability on the Company's condensed consolidated balance sheets. Operating lease commitments related to this lease are included in the table below within property facility leases. The following table provides details of the Company's future minimum lease payments under finance lease liabilities and operating lease liabilities recorded on the Company's condensed consolidated balance sheets as of March 31, 2022. The table does not include commitments that are contingent on events or other factors that are currently uncertain or unknown. Finance Leases Operating Leases Aircraft and Spare Engine Leases Property Facility Leases Other Total (in thousands) Remainder of 2022 $ 631 $ 199,747 $ 4,153 $ 118 $ 204,649 2023 465 260,628 5,548 13 266,654 2024 215 248,019 3,810 — 252,044 2025 117 229,777 1,192 — 231,086 2026 39 203,517 964 — 204,520 2027 and thereafter — 1,660,329 142,174 — 1,802,503 Total minimum lease payments $ 1,467 $ 2,802,017 $ 157,841 $ 131 $ 2,961,456 Less amount representing interest 72 826,808 133,060 1 959,941 Present value of minimum lease payments $ 1,395 $ 1,975,209 $ 24,781 $ 130 $ 2,001,515 Less current portion 761 160,378 4,306 130 165,575 Long-term portion $ 634 $ 1,814,831 $ 20,475 $ — $ 1,835,940 Commitments related to the Company's noncancellable short-term operating leases not recorded on the Company's condensed consolidated balance sheets are expected to be $4.5 million for the remainder of 2022 and none for 2023 and beyond. The table below presents information for lease costs related to the Company's finance and operating leases: Three Months Ended March 31, 2022 2021 (in thousands) Finance lease cost Amortization of leased assets $ 188 $ 168 Interest of lease liabilities 18 24 Operating lease cost Operating lease cost (1) 63,251 52,141 Short-term lease cost (1) 10,257 7,015 Variable lease cost (1) 48,694 38,149 Total lease cost $ 122,408 $ 97,497 (1) Expenses are classified within aircraft rent and landing fees and other rents on the Company's condensed consolidated statements of operations. The table below presents lease terms and discount rates related to the Company's finance and operating leases: March 31, 2022 March 31, 2021 Weighted-average remaining lease term Operating leases 14.0 years 13.2 years Finance leases 2.3 years 2.4 years Weighted-average discount rate Operating leases 5.62 % 6.06 % Finance leases 4.71 % 5.52 %

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Aircraft-Related Commitments and Financing Arrangements The Company’s contractual purchase commitments consist primarily of aircraft and engine acquisitions through manufacturers and aircraft leasing companies. As of March 31, 2022, the Company's total firm aircraft orders consisted of 117 A320 family aircraft with Airbus, including A319neos, A320neos and A321neos, with deliveries expected through 2027. Out of these 117 aircraft, the Company has 14 aircraft scheduled for delivery in the remainder of 2022 and 17 aircraft scheduled for delivery in 2023. During the third quarter of 2021, the Company entered into an Engine Purchase Support Agreement which requires the Company to purchase a certain number of spare engines in order to maintain a contractual ratio of spare engines to aircraft in the fleet. As of March 31, 2022, the Company is committed to purchase 15 PW1100G-JM spare engines, with deliveries through 2027. As of March 31, 2022, purchase commitments for these aircraft and engines, including estimated amounts for contractual price escalations and pre-delivery payments, are expected to be $727.3 million for the remainder of 2022, $906.9 million in 2023, $999.4 million in 2024, $1,060.7 million in 2025, $1,349.9 million in 2026, and $872.8 million in 2027 and beyond. During the third quarter of 2019, the United States announced its decision to levy tariffs on certain imports from the European Union, including commercial aircraft and related parts. These tariffs include aircraft and other parts that the Company is already contractually obligated to purchase including those reflected above. In June 2021, the United States Trade Representative announced that the United States and European Union had agreed to suspend reciprocal tariffs on large civilian aircraft for five years, pending discussions to resolve their trade dispute. In addition to the aircraft purchase agreement, as of March 31, 2022, the Company has agreements in place for 40 A320neos and A321neos to be financed through direct leases with third-party lessors with deliveries scheduled from the remainder of 2022 through 2024. As of March 31, 2022, the Company had secured financing for 14 aircraft, scheduled for delivery from Airbus through the remainder of 2022, which will be financed through sale leaseback transactions. The contractual purchase amounts for these aircraft are included within the purchase commitments above. As of March 31, 2022, the Company did not have financing commitments in place for the remaining 103 Airbus aircraft on firm order through 2027. However, the Company has a financing letter of agreement with Airbus which provides backstop financing for a majority of the aircraft included in the A320 NEO Family Purchase Agreement signed in the fourth quarter of 2019. The agreement provides a standby credit facility in the form of senior secured mortgage debt financing. As of March 31, 2022, aircraft rent commitments for future aircraft deliveries to be financed under direct leases from third-party lessors and sale leaseback transactions are expected to be approximately $30.2 million for the remainder of 2022, $124.9 million in 2023, $202.3 million in 2024, $231.2 million in 2025, $231.2 million in 2026, and $1,954.2 million in 2027 and beyond. Interest commitments related to the secured debt financing of 73 delivered aircraft as of March 31, 2022 are $56.7 million for the remainder of 2022, $64.6 million in 2023, $53.3 million in 2024, $45.8 million in 2025, $38.3 million in 2026, and $90.3 million in 2027 and beyond. As of March 31, 2022, interest commitments related to the Company's 8.00% senior secured notes, convertible debt financing, unsecured term loans and revolving credit facility are $37.9 million for the remainder of 2022, $48.5 million in 2023, $48.5 million in 2024, $45.5 million in 2025, $5.9 million in 2026, and $14.0 million in 2027 and beyond. For principal commitments related to the Company's debt financing, refer to Note 12, Debt and Other Obligations. The Company is contractually obligated to pay the following minimum guaranteed payments for its reservation system, construction commitments related to its new headquarters campus and other miscellaneous subscriptions and services as of March 31, 2022: $29.6 million for the remainder of 2022, $21.1 million in 2023, $17.4 million in 2024, $17.4 million in 2025, $16.8 million in 2026, and $18.8 million in 2027 and thereafter. During the first quarter of 2018, the Company entered into a contract renewal with its reservation system provider which expires in 2028. Litigation and Assessments The Company is subject to commercial litigation claims and to administrative and regulatory proceedings and reviews that may be asserted or maintained from time to time. The Company believes the ultimate outcome of such lawsuits, proceedings and reviews will not, individually or in the aggregate, have a material adverse effect on its financial position, liquidity or results of operations. In making a determination regarding accruals, using available information, the Company evaluates the likelihood of an unfavorable outcome in legal or regulatory proceedings and assessments to which the Company is a party and records a loss contingency when it is probable a liability has been incurred and the amount of the loss can be reasonably estimated. These subjective determinations are based on the status of such legal or regulatory proceedings, the merits of the Company's defenses, and consultation with legal counsel. Actual outcomes of these legal and regulatory proceedings may materially differ from the Company's current estimates. It is possible that resolution of one or more of the legal matters currently pending or threatened could result in losses material to the Company's consolidated results of operations, liquidity, or financial condition. Following an audit by the Internal Revenue Service (IRS) related to the collection of federal excise taxes on optional passenger seat selection charges covering the period of the second quarter 2018 through the fourth quarter 2020, on March 31, 2022, the Company was assessed $34.9 million. The Company believes a loss in this matter is not probable and has not recognized a loss contingency. Credit Card Processing Arrangements The Company has agreements with organizations that process credit card transactions arising from the purchase of air travel, baggage charges, and other ancillary services by customers. As is standard in the airline industry, the Company's contractual arrangements with credit card processors permit them, under certain circumstances, to retain a holdback or other collateral, which the Company records as restricted cash, when future air travel and other future services are purchased via credit card transactions. The required holdback is the percentage of the Company's overall credit card sales that its credit card processors hold to cover refunds to customers if the Company fails to fulfill its flight obligations. The Company's credit card processors do not require the Company to maintain cash collateral provided that the Company satisfies certain liquidity and other financial covenants. Failure to meet these covenants would provide the processors the right to place a holdback resulting in a commensurate reduction of unrestricted cash. As of March 31, 2022 and December 31, 2021, the Company's credit card processors were holding back no remittances. The maximum potential exposure to cash holdbacks by the Company's credit card processors, based upon advance ticket sales and Spirit Saver$ Club ® memberships as of March 31, 2022 and December 31, 2021, was $632.6 million and $371.8 million, respectively. Employees The Company has 5 union-represented employee groups that together represented approximately 80% of all employees as of March 31, 2022. The table below sets forth the Company's employee groups and status of the collective bargaining agreements as of March 31, 2022. Employee Groups Representative Amendable Date (1) Percentage of Workforce Pilots Air Line Pilots Association, International ("ALPA") February 2023 27% Flight Attendants Association of Flight Attendants ("AFA-CWA") September 2021 47% Dispatchers Professional Airline Flight Control Association ("PAFCA") October 2023 1% Ramp Service Agents International Association of Machinists and Aerospace Workers ("IAMAW") November 2026 3% Passenger Service Agents Transport Workers Union of America ("TWU") February 2027 2% (1) Subject to standard early opener provisions. The Company's passenger service agents are represented by the TWU, but the representation applies only to the Company's Fort Lauderdale station where the Company has direct employees in the passenger service classification. The Company and the TWU began meeting in late October 2018 to negotiate an initial collective bargaining agreement. During February 2022, the Company reached a tentative agreement with the TWU. The Company's passenger service agents ratified the five-year agreement on February 21, 2022. In February 2021, the Company entered into a Letter of Agreement with the AFA-CWA to change the amendable date of the collective bargaining agreement from May 4, 2021 to September 1, 2021. All other terms of the collective bargaining agreement remained the same. In June 2021, the AFA-CWA notified the Company, as required by the Railway Labor Act, that it intends to submit proposed changes to the collective bargaining agreement covering the Company’s flight attendants. The Company and the AFA-CWA began the negotiation sessions on September 27, 2021. As of March 31, 2022, the Company continued to negotiate with the AFA-CWA.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value MeasurementsUnder ASC 820, "Fair Value Measurements and Disclosures," disclosures relating to how fair value is determined for assets and liabilities are required, and a hierarchy for which these assets and liabilities must be grouped is established, based on significant levels of inputs, as follows: 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. 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. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The Company utilizes several valuation techniques in order to assess the fair value of the Company’s financial assets and liabilities. Long-Term Debt The estimated fair value of the Company's secured notes, term loan debt agreements and revolving credit facilities have been determined to be Level 3 as certain inputs used to determine the fair value of these agreements are unobservable. The Company utilizes a discounted cash flow method to estimate the fair value of the Level 3 long-term debt. The estimated fair value of the Company's publicly and non-publicly held EETC debt agreements and the Company's convertible notes has been determined to be Level 2 as the Company utilizes quoted market prices in markets with low trading volumes to estimate the fair value of its Level 2 long-term debt. The carrying amounts and estimated fair values of the Company's long-term debt at March 31, 2022 and December 31, 2021 were as follows: March 31, 2022 December 31, 2021 Fair Value Level Hierarchy Carrying Value Estimated Fair Value Carrying Value Estimated Fair Value (in millions) 8.00% senior secured notes $ 510.0 $ 504.8 $ 510.0 $ 530.4 Level 3 Fixed-rate term loans 1,190.9 1,168.7 1,223.5 1,262.6 Level 3 Unsecured term loans 136.3 132.7 136.3 146.4 Level 3 2015-1 EETC Class A 300.6 294.0 300.6 311.1 Level 2 2015-1 EETC Class B 56.0 54.9 56.0 56.4 Level 2 2015-1 EETC Class C 75.2 73.3 75.2 74.0 Level 2 2017-1 EETC Class AA 193.3 184.8 200.3 203.3 Level 2 2017-1 EETC Class A 64.4 60.4 66.8 65.8 Level 2 2017-1 EETC Class B 53.4 48.9 55.8 53.6 Level 2 2017-1 EETC Class C 85.5 83.5 85.5 84.1 Level 2 4.75% convertible notes due 2025 28.2 55.7 28.2 55.6 Level 2 1.00% convertible notes due 2026 500.0 448.4 500.0 432.5 Level 2 Total long-term debt $ 3,193.8 $ 3,110.1 $ 3,238.2 $ 3,275.8 Cash and Cash Equivalents Cash and cash equivalents at March 31, 2022 and December 31, 2021 are comprised of liquid money market funds and cash, and are categorized as Level 1 instruments. The Company maintains cash with various high-quality financial institutions. Restricted Cash Restricted cash is comprised of cash held in an account subject to account control agreements or otherwise pledged as collateral against the Company's letters of credit and is categorized as a Level 1 instrument. As of March 31, 2022, the Company had $85.0 million in standby letters of credit secured by $75.0 million of restricted cash, of which $27.0 million had been drawn upon for issued letters of credit. In addition, the Company had $20.4 million of restricted cash held in accounts subject to control agreements to be used for the payment of interest and fees on the 8.00% senior secured notes. Short-term Investment Securities Short-term investment securities at March 31, 2022 and December 31, 2021 are classified as available-for-sale and generally consist of U.S. Treasury and U.S. government agency securities with contractual maturities of 12 months or less. The Company's short-term investment securities are categorized as Level 1 instruments, as the Company uses quoted market prices in active markets when determining the fair value of these securities. For additional information, refer to Note 7, Short-term Investment Securities. Derivative Liability As a result of the settlement terms stipulated by the Merger Agreement, as of the Merger Agreement date, the convertible notes due 2026 no longer qualify for the derivative accounting scope exception provided under ASC 815. As such, the Company was required to bifurcate the fair value of the conversion option of the convertible notes due 2026 as a derivative liability as of the Merger Agreement date with subsequent changes in fair value recorded in earnings. As of February 5, 2022, the Company recorded the fair value of the embedded derivative of $49.5 million as a derivative liability within deferred gains and other long-term liabilities and a debt discount within long-term debt and finance leases, less current maturities on its condensed consolidated balance sheets. The fair value of the derivative liability was estimated as the difference in value of the traded price of the convertible notes, including the conversion option and the value of the convertible notes in the absence of the conversion option (the debt component). The debt component was estimated using a discounted cash flow analysis with a yield calibrated to the traded price of the convertible notes. The fair value of the derivative liability has been determined to be Level 2 as observable inputs were used to determine the fair value of derivative liability. For additional information, refer to Note 12, Debt and Other Obligations. Assets and liabilities measured at gross fair value on a recurring basis are summarized below: Fair Value Measurements as of March 31, 2022 Total Level Level Level (in millions) Cash and cash equivalents $ 1,247.9 $ 1,247.9 $ — $ — Restricted cash 95.4 95.4 — — Short-term investment securities 106.0 106.0 — — Assets held for sale 2.5 — — 2.5 Total assets $ 1,451.8 $ 1,449.3 $ — $ 2.5 Derivative liability $ 48.6 $ — $ 48.6 $ — Total liabilities $ 48.6 $ — $ 48.6 $ — Fair Value Measurements as of December 31, 2021 Total Level Level Level (in millions) Cash and cash equivalents $ 1,333.5 $ 1,333.5 $ — $ — Restricted cash 95.4 95.4 — — Short-term investment securities 106.3 106.3 — — Assets held for sale 2.5 — — 2.5 Total assets $ 1,537.7 $ 1,535.2 $ — $ 2.5 Total liabilities $ — $ — $ — $ —

Debt and Other Obligations

Debt and Other Obligations	3 Months Ended
	Mar. 31, 2022
Debt Disclosure [Abstract]
Debt and Other Obligations	Debt and Other Obligations As of March 31, 2022, the Company had outstanding public and non-public debt instruments. Revolving credit facility due in 2024 On March 30, 2020, the Company entered into a revolving credit facility for $110.0 million, with an option to increase the overall commitment amount up to $350 million with the consent of any participating lenders and subject to borrowing base availability. In the second quarter of 2020, the commitment was increased to $180.0 million and during the first quarter of 2021, the commitment was further increased to $240.0 million . As of March 31, 2022 and December 31, 2021, the Company had $240.0 million undrawn and available under this facility. Any amounts drawn on this facility are included in long-term debt and finance leases, less current maturities on the Company's condensed consolidated balance sheets. During the first quarter of 2021, the maturity date of the facility was extended for two Convertible senior notes due 2025 On May 12, 2020, the Company completed the public offering of $175.0 million aggregate principal amount of 4.75% convertible senior notes due 2025 ("convertible notes due 2025"). As of March 31, 2022, the if-converted value exceeds the principal amount of the convertible notes by $22.4 million, using the average stock price for the three months ended March 31, 2022. Since the notes are currently convertible in accordance with the terms of the indenture governing such notes, the Company had $28.2 million recorded within c urrent maturities of long-term debt and finance leases on its condensed consolidated balance sheets as of March 31, 2022 related to its convertible senior notes due 2025. Noteholders may convert their notes at their option only in the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on June 30, 2020 (and only during such calendar quarter), if the last reported sale price per share of the Company’s common stock exceeds 130% of the conversion price for each of at least 20 trading days (whether or not consecutive) during the 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter; (2) during the five consecutive business days immediately after any five consecutive trading day period (such five consecutive trading day period, the “measurement period”) in which the trading price per $1,000 principal amount of notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price per share of the Company’s common stock on such trading day and the conversion rate on such trading day; (3) upon the occurrence of certain corporate events or distributions on the Company’s common stock; and (4) at any time from, and including, February 18, 2025 until the close of business on the second scheduled trading day immediately before the maturity date. As of March 31, 2022, the notes may be converted by noteholders through June 30, 2022. No notes were converted during the three months ended March 31, 2022. Upon conversion, the Company will pay or deliver, as the case may be, cash, shares of the Company’s common stock or a combination of cash and shares of common stock, at the Company’s election. Based on the terms of the Merger Agreement executed on February 5, 2022 (the Merger Agreement date), upon conversion of any notes through the closing or termination of the merger, the conversion value, including the principal amount, will be paid all in shares of the Company's common stock. The initial conversion rate is 78.4314 shares of voting common stock per $1,000 principal amount of convertible notes (equivalent to an initial conversion price of approximately $12.75 per share of common stock). The conversion rate will be subject to adjustment in some events but will not be adjusted for any accrued and unpaid interest. Convertible senior notes due 2026 On April 30, 2021, the Company completed the public offering of $500.0 million aggregate principal amount of 1.00% convertible senior notes due 2026 ("convertible notes due 2026"). Noteholders may convert their notes at their option only in the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on June 30, 2021 (and only during such calendar quarter), if the last reported sale price per share of the Company’s common stock exceeds 130% of the conversion price for each of at least 20 trading days (whether or not consecutive) during the 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter; (2) during the five consecutive business days immediately after any five consecutive trading day period (such five consecutive trading day period, the “measurement period”) in which the trading price per $1,000 principal amount of notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price per share of the Company’s common stock on such trading day and the conversion rate on such trading day; (3) upon the occurrence of certain corporate events or distributions on the Company’s common stock; (4) if the Company calls such notes for redemption; and (5) at any time from, and including, February 17, 2026 until the close of business on the second scheduled trading day immediately before the maturity date. As of March 31, 2022, the notes did not qualify for conversion by noteholders through June 30, 2022. Based on the terms of the indenture, the Company will have the right to elect to settle conversions in cash, shares of the Company’s common stock or a combination of cash and shares of common stock. However, upon conversion of any notes, the conversion value will be paid in cash up to at least the principal amount of the notes being converted. Based on the terms of the Merger Agreement with Frontier executed on February 5, 2022 (the Merger Agreement date), upon conversion of any notes through the closing or termination of the merger, the conversion value, including the principal amount, will be paid all in cash. The conversion value will be determined over an observation period consisting of 40 trading days, will be paid in cash up to at least the principal amount of the notes being converted. The initial conversion rate is 20.3791 shares of voting common stock per $1,000 principal amount of convertible notes (equivalent to an initial conversion price of approximately $49.07 per share of common stock). The conversion rate will be subject to adjustment in some events but will not be adjusted for any accrued and unpaid interest. The notes will be redeemable, in whole or in part (subject to certain limitations described below), at the Company’s option at any time, and from time to time, on or after May 15, 2024 and on or before the 40th scheduled trading day immediately before the maturity date, at a cash redemption price equal to the principal amount of the notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date, but only if the last reported sale price per share of the Company's common stock exceeds 130% of the conversion price for a specified period of time. However, the Company may not redeem less than all of the outstanding notes unless at least $150.0 million aggregate principal amount of notes are outstanding and not called for redemption as of the time the Company sends the related redemption notice . As a result of the settlement terms stipulated by the Merger Agreement, as of the Merger Agreement date, the notes no longer qualify for the derivative accounting scope exception provided under ASC 815. As such, the Company was required to bifurcate the fair value of the conversion option of the convertible senior notes due 2026 as a derivative liability as of the Merger Agreement date with subsequent changes in fair value recorded in earnings. As of February 5, 2022, the Company recorded the fair value of the embedded derivative of $49.5 million as a derivative liability within deferred gains and other long-term liabilities and a debt discount within long-term debt and finance leases, less current maturities on its condensed consolidated balance sheets. The debt discount will be amortized through interest expense, using the effective interest rate method, over the remaining life of the instrument. In addition, during the three months ended March 31, 2022, the Company recorded an adjustment to the derivative liability of $0.9 million within interest expense on its condensed consolidated statement of operations. Since the notes are currently not convertible in accordance with the terms of the indenture governing such notes, the Company had $453.0 million, net of the related unamortized debt discount of $47.0 million, recorded within long-term debt and finance leases, less current maturities on the Company's condensed consolidated balance sheets as of March 31, 2022 related to its convertible senior notes due 2026. Long-term debt is comprised of the following: As of As of March 31, 2022 December 31, 2021 March 31, 2022 December 31, 2021 (in millions) (weighted-average interest rates) 8.00% senior secured notes due 2025 $ 510.0 $ 510.0 8.00 % 8.00 % Fixed-rate loans due through 2039 (1) 1,190.9 1,223.5 3.52 % 3.52 % Unsecured term loans due in 2031 136.3 136.3 1.00 % 1.00 % Fixed-rate class A 2015-1 EETC due through 2028 300.6 300.6 4.10 % 4.10 % Fixed-rate class B 2015-1 EETC due through 2024 56.0 56.0 4.45 % 4.45 % Fixed-rate class C 2015-1 EETC due through 2023 75.2 75.2 4.93 % 4.93 % Fixed-rate class AA 2017-1 EETC due through 2030 193.3 200.3 3.38 % 3.38 % Fixed-rate class A 2017-1 EETC due through 2030 64.4 66.8 3.65 % 3.65 % Fixed-rate class B 2017-1 EETC due through 2026 53.4 55.8 3.80 % 3.80 % Fixed-rate class C 2017-1 EETC due through 2023 85.5 85.5 5.11 % 5.11 % Convertible notes due 2025 28.2 28.2 4.75 % 4.75 % Convertible notes due 2026 500.0 500.0 1.00 % 1.00 % Long-term debt $ 3,193.8 $ 3,238.2 Less current maturities 293.2 208.2 Less unamortized discounts, net 99.4 54.9 Total $ 2,801.2 $ 2,975.1 (1) Includes obligations related to one aircraft recorded as a failed sale leaseback. Refer to Note 9, Leases for additional information. During the three months ended March 31, 2022, the Company made scheduled principal payments of $44.3 million on its outstanding debt obligations. During the three months ended March 31, 2021, the Company made scheduled principal payments of $135.9 million on its outstanding debt obligations. At March 31, 2022, long-term debt principal payments for the next five years and thereafter are as follows: March 31, 2022 (in millions) remainder of 2022 $ 148.7 2023 336.6 2024 222.1 2025 726.6 2026 731.1 2027 and beyond 1,028.7 Total debt principal payments $ 3,193.8 Interest Expense Interest expense related to long-term debt and finance leases consists of the following: Three Months Ended March 31, 2022 2021 (in thousands) 8.00% senior secured notes (1) $ 10,461 $ 17,434 Fixed-rate term loans 10,684 10,903 Unsecured term loans 336 199 Class A 2015-1 EETC 3,048 3,275 Class B 2015-1 EETC 616 705 Class C 2015-1 EETC 917 1,056 Class AA 2017-1 EETC 1,638 1,755 Class A 2017-1 EETC 590 633 Class B 2017-1 EETC 512 557 Class C 2017-1 EETC 1,080 1,080 Convertible notes (2) 3,223 2,078 Revolving credit facilities — 1,170 Finance leases 18 24 Commitment and other fees 535 428 Amortization of deferred financing costs 4,222 3,509 Total $ 37,880 $ 44,806 (1) Includes $0.3 million and $0.4 million of accretion and $10.2 million and $17.0 million of interest expense for the three months ended March 31, 2022 and March 31, 2021, respectively. (2) Includes $2.5 million of amortization of the discount for the convertible notes due 2026, $1.6 million of interest expense for the convertible notes due 2025 and 2026 offset by $0.9 million of mark-to-market adjustments for the convertible notes due 2026 for the three months ended March 31, 2022. Includes $2.1 million of interest expense for the convertible notes due 2025 for the three months ended March 31, 2021.

Basis of Presentation (Policies

Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Accounting	These unaudited condensed consolidated financial statements reflect all normal recurring adjustments which management believes are necessary to fairly present the financial position, results of operations and cash flows of the Company for the respective periods presented. Certain information and footnote disclosures normally included in the audited annual financial statements prepared in accordance with U.S. generally accepted accounting principles ("GAAP") have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission for Form 10-Q. These unaudited interim condensed consolidated financial statements should be read in conjunction with the audited financial statements of the Company and notes thereto included in the Company's Annual Report on Form 10-K for the year ended December 31, 2021 filed with the Securities and Exchange Commission on February 8, 2022.
Use of Estimates	The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect both 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 may differ from these estimates.

Revenue (Tables)

Revenue (Tables)	3 Months Ended
	Mar. 31, 2022
Revenue from Contract with Customer [Abstract]
Schedule of Revenue Disaggregation	The following table shows disaggregated operating revenues for the three months ended March 31, 2022 and 2021. Three Months Ended March 31, 2022 2021 (in thousands) Operating revenues: Fare $ 418,418 $ 174,287 Non-fare 531,326 276,048 Total passenger revenues 949,744 450,335 Other 17,571 10,944 Total operating revenues $ 967,315 $ 461,279 Three Months Ended March 31, 2022 2021 (in thousands) DOT—Domestic $ 827,054 $ 408,693 DOT—Latin America 140,261 52,586 Total $ 967,315 $ 461,279

Loss per Share (Tables)

Loss per Share (Tables)	3 Months Ended
	Mar. 31, 2022
Earnings Per Share [Abstract]
Computation of Basic and Diluted Loss per Common Share	The following table sets forth the computation of basic and diluted loss per common share: Three Months Ended March 31, 2022 2021 (in thousands, except per-share amounts) Numerator Net loss $ (194,703) $ (112,321) Denominator Weighted-average shares outstanding, basic 108,581 97,775 Effect of dilutive shares — — Adjusted weighted-average shares outstanding, diluted 108,581 97,775 Loss per share Basic loss per common share $ (1.79) $ (1.15) Diluted loss per common share $ (1.79) $ (1.15)

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	3 Months Ended
	Mar. 31, 2022
Payables and Accruals [Abstract]
Accrued Liabilities Included in Other Current Liabilities	Other current liabilities as of March 31, 2022 and December 31, 2021 consist of the following: March 31, 2022 December 31, 2021 (in thousands) Salaries, wages and benefits $ 140,017 $ 142,893 Federal excise and other passenger taxes and fees payable 122,107 77,409 Airport obligations 94,505 85,772 Fuel 62,355 55,103 Aircraft maintenance 46,768 39,178 Interest payable 26,080 24,526 Aircraft and facility lease obligations 18,240 23,049 Other 36,661 32,824 Other current liabilities $ 546,733 $ 480,754

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2022
Leases [Abstract]
Schedule of Finance Lease Maturities	The following table provides details of the Company's future minimum lease payments under finance lease liabilities and operating lease liabilities recorded on the Company's condensed consolidated balance sheets as of March 31, 2022. The table does not include commitments that are contingent on events or other factors that are currently uncertain or unknown. Finance Leases Operating Leases Aircraft and Spare Engine Leases Property Facility Leases Other Total (in thousands) Remainder of 2022 $ 631 $ 199,747 $ 4,153 $ 118 $ 204,649 2023 465 260,628 5,548 13 266,654 2024 215 248,019 3,810 — 252,044 2025 117 229,777 1,192 — 231,086 2026 39 203,517 964 — 204,520 2027 and thereafter — 1,660,329 142,174 — 1,802,503 Total minimum lease payments $ 1,467 $ 2,802,017 $ 157,841 $ 131 $ 2,961,456 Less amount representing interest 72 826,808 133,060 1 959,941 Present value of minimum lease payments $ 1,395 $ 1,975,209 $ 24,781 $ 130 $ 2,001,515 Less current portion 761 160,378 4,306 130 165,575 Long-term portion $ 634 $ 1,814,831 $ 20,475 $ — $ 1,835,940
Schedule of Operating Lease Maturities	The following table provides details of the Company's future minimum lease payments under finance lease liabilities and operating lease liabilities recorded on the Company's condensed consolidated balance sheets as of March 31, 2022. The table does not include commitments that are contingent on events or other factors that are currently uncertain or unknown. Finance Leases Operating Leases Aircraft and Spare Engine Leases Property Facility Leases Other Total (in thousands) Remainder of 2022 $ 631 $ 199,747 $ 4,153 $ 118 $ 204,649 2023 465 260,628 5,548 13 266,654 2024 215 248,019 3,810 — 252,044 2025 117 229,777 1,192 — 231,086 2026 39 203,517 964 — 204,520 2027 and thereafter — 1,660,329 142,174 — 1,802,503 Total minimum lease payments $ 1,467 $ 2,802,017 $ 157,841 $ 131 $ 2,961,456 Less amount representing interest 72 826,808 133,060 1 959,941 Present value of minimum lease payments $ 1,395 $ 1,975,209 $ 24,781 $ 130 $ 2,001,515 Less current portion 761 160,378 4,306 130 165,575 Long-term portion $ 634 $ 1,814,831 $ 20,475 $ — $ 1,835,940
Schedule of Lease Cost	The table below presents information for lease costs related to the Company's finance and operating leases: Three Months Ended March 31, 2022 2021 (in thousands) Finance lease cost Amortization of leased assets $ 188 $ 168 Interest of lease liabilities 18 24 Operating lease cost Operating lease cost (1) 63,251 52,141 Short-term lease cost (1) 10,257 7,015 Variable lease cost (1) 48,694 38,149 Total lease cost $ 122,408 $ 97,497 (1) Expenses are classified within aircraft rent and landing fees and other rents on the Company's condensed consolidated statements of operations. The table below presents lease terms and discount rates related to the Company's finance and operating leases: March 31, 2022 March 31, 2021 Weighted-average remaining lease term Operating leases 14.0 years 13.2 years Finance leases 2.3 years 2.4 years Weighted-average discount rate Operating leases 5.62 % 6.06 % Finance leases 4.71 % 5.52 %

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Employee Groups and Status of the Collective Bargaining Agreements	The table below sets forth the Company's employee groups and status of the collective bargaining agreements as of March 31, 2022. Employee Groups Representative Amendable Date (1) Percentage of Workforce Pilots Air Line Pilots Association, International ("ALPA") February 2023 27% Flight Attendants Association of Flight Attendants ("AFA-CWA") September 2021 47% Dispatchers Professional Airline Flight Control Association ("PAFCA") October 2023 1% Ramp Service Agents International Association of Machinists and Aerospace Workers ("IAMAW") November 2026 3% Passenger Service Agents Transport Workers Union of America ("TWU") February 2027 2%

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Carrying Amount and Estimated Fair Value, Long-term Debt	The carrying amounts and estimated fair values of the Company's long-term debt at March 31, 2022 and December 31, 2021 were as follows: March 31, 2022 December 31, 2021 Fair Value Level Hierarchy Carrying Value Estimated Fair Value Carrying Value Estimated Fair Value (in millions) 8.00% senior secured notes $ 510.0 $ 504.8 $ 510.0 $ 530.4 Level 3 Fixed-rate term loans 1,190.9 1,168.7 1,223.5 1,262.6 Level 3 Unsecured term loans 136.3 132.7 136.3 146.4 Level 3 2015-1 EETC Class A 300.6 294.0 300.6 311.1 Level 2 2015-1 EETC Class B 56.0 54.9 56.0 56.4 Level 2 2015-1 EETC Class C 75.2 73.3 75.2 74.0 Level 2 2017-1 EETC Class AA 193.3 184.8 200.3 203.3 Level 2 2017-1 EETC Class A 64.4 60.4 66.8 65.8 Level 2 2017-1 EETC Class B 53.4 48.9 55.8 53.6 Level 2 2017-1 EETC Class C 85.5 83.5 85.5 84.1 Level 2 4.75% convertible notes due 2025 28.2 55.7 28.2 55.6 Level 2 1.00% convertible notes due 2026 500.0 448.4 500.0 432.5 Level 2 Total long-term debt $ 3,193.8 $ 3,110.1 $ 3,238.2 $ 3,275.8
Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis	Assets and liabilities measured at gross fair value on a recurring basis are summarized below: Fair Value Measurements as of March 31, 2022 Total Level Level Level (in millions) Cash and cash equivalents $ 1,247.9 $ 1,247.9 $ — $ — Restricted cash 95.4 95.4 — — Short-term investment securities 106.0 106.0 — — Assets held for sale 2.5 — — 2.5 Total assets $ 1,451.8 $ 1,449.3 $ — $ 2.5 Derivative liability $ 48.6 $ — $ 48.6 $ — Total liabilities $ 48.6 $ — $ 48.6 $ — Fair Value Measurements as of December 31, 2021 Total Level Level Level (in millions) Cash and cash equivalents $ 1,333.5 $ 1,333.5 $ — $ — Restricted cash 95.4 95.4 — — Short-term investment securities 106.3 106.3 — — Assets held for sale 2.5 — — 2.5 Total assets $ 1,537.7 $ 1,535.2 $ — $ 2.5 Total liabilities $ — $ — $ — $ —

Debt and Other Obligations (Tab

Debt and Other Obligations (Tables)	3 Months Ended
	Mar. 31, 2022
Debt Disclosure [Abstract]
Schedule of Long-term Debt	Long-term debt is comprised of the following: As of As of March 31, 2022 December 31, 2021 March 31, 2022 December 31, 2021 (in millions) (weighted-average interest rates) 8.00% senior secured notes due 2025 $ 510.0 $ 510.0 8.00 % 8.00 % Fixed-rate loans due through 2039 (1) 1,190.9 1,223.5 3.52 % 3.52 % Unsecured term loans due in 2031 136.3 136.3 1.00 % 1.00 % Fixed-rate class A 2015-1 EETC due through 2028 300.6 300.6 4.10 % 4.10 % Fixed-rate class B 2015-1 EETC due through 2024 56.0 56.0 4.45 % 4.45 % Fixed-rate class C 2015-1 EETC due through 2023 75.2 75.2 4.93 % 4.93 % Fixed-rate class AA 2017-1 EETC due through 2030 193.3 200.3 3.38 % 3.38 % Fixed-rate class A 2017-1 EETC due through 2030 64.4 66.8 3.65 % 3.65 % Fixed-rate class B 2017-1 EETC due through 2026 53.4 55.8 3.80 % 3.80 % Fixed-rate class C 2017-1 EETC due through 2023 85.5 85.5 5.11 % 5.11 % Convertible notes due 2025 28.2 28.2 4.75 % 4.75 % Convertible notes due 2026 500.0 500.0 1.00 % 1.00 % Long-term debt $ 3,193.8 $ 3,238.2 Less current maturities 293.2 208.2 Less unamortized discounts, net 99.4 54.9 Total $ 2,801.2 $ 2,975.1 (1) Includes obligations related to one aircraft recorded as a failed sale leaseback. Refer to Note 9, Leases for additional information.
Schedule of Maturities of Long-term Debt	At March 31, 2022, long-term debt principal payments for the next five years and thereafter are as follows: March 31, 2022 (in millions) remainder of 2022 $ 148.7 2023 336.6 2024 222.1 2025 726.6 2026 731.1 2027 and beyond 1,028.7 Total debt principal payments $ 3,193.8
Schedule of Interest Expense, Long-term Debt	Interest expense related to long-term debt and finance leases consists of the following: Three Months Ended March 31, 2022 2021 (in thousands) 8.00% senior secured notes (1) $ 10,461 $ 17,434 Fixed-rate term loans 10,684 10,903 Unsecured term loans 336 199 Class A 2015-1 EETC 3,048 3,275 Class B 2015-1 EETC 616 705 Class C 2015-1 EETC 917 1,056 Class AA 2017-1 EETC 1,638 1,755 Class A 2017-1 EETC 590 633 Class B 2017-1 EETC 512 557 Class C 2017-1 EETC 1,080 1,080 Convertible notes (2) 3,223 2,078 Revolving credit facilities — 1,170 Finance leases 18 24 Commitment and other fees 535 428 Amortization of deferred financing costs 4,222 3,509 Total $ 37,880 $ 44,806 (1) Includes $0.3 million and $0.4 million of accretion and $10.2 million and $17.0 million of interest expense for the three months ended March 31, 2022 and March 31, 2021, respectively. (2) Includes $2.5 million of amortization of the discount for the convertible notes due 2026, $1.6 million of interest expense for the convertible notes due 2025 and 2026 offset by $0.9 million of mark-to-market adjustments for the convertible notes due 2026 for the three months ended March 31, 2022. Includes $2.1 million of interest expense for the convertible notes due 2025 for the three months ended March 31, 2021.

Basis of Presentation (Details)

Basis of Presentation (Details)	Mar. 31, 2022	Aug. 31, 2020
8.00% Senior Secured Notes Due 2025 | Secured Debt
Debt Instrument [Line Items]
Stated interest rate percentage	8.00%	8.00%

Merger (Details)

Merger (Details) - USD ($) $ / shares in Units, $ in Millions	Feb. 05, 2022	Apr. 05, 2022
Subsequent Event | JetBlue Airways
Business Acquisition [Line Items]
Unsolicited proposal from JetBlue airways to acquire all of the outstanding shares (in dollars per share)		$ 33
Frontier Merger Agreement
Business Acquisition [Line Items]
Business acquisition, cash per share to be received (in dollars per share)	$ 2.13
Business acquisition, number of shares to be received per share (in shares)	1.9126
Common stock, par value (in dollars per share)	$ 0.001
Percentage of outstanding shares owned	48.50%
Business acquisition, breakup fee	$ 94.2

Revenue (Details)

Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 967,315	$ 461,279
Air traffic liability	558,303		$ 382,317
DOT—Domestic
Disaggregation of Revenue [Line Items]
Total operating revenues	827,054	408,693
DOT—Latin America
Disaggregation of Revenue [Line Items]
Total operating revenues	140,261	52,586
Total passenger revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	949,744	450,335
Fare
Disaggregation of Revenue [Line Items]
Total operating revenues	418,418	174,287
Non-fare
Disaggregation of Revenue [Line Items]
Total operating revenues	531,326	276,048
Other
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 17,571	$ 10,944

Loss on Disposal (Details)

Loss on Disposal (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022USD ($)aircraftaircraft_engine	Mar. 31, 2021USD ($)
Discontinued Operations and Disposal Groups [Abstract]
Loss on disposal of assets	$ 11,552	$ 1,117
Impairment of long-lived assets to be disposed of	$ 6,600
Number of impaired spare engine related to loss on disposal | aircraft_engine	1
Loss on sale-leaseback transaction	$ 4,300
Number of aircraft related to loss | aircraft	3

Special Charges (Credits) (Deta

Special Charges (Credits) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Unusual or Infrequent Item, or Both [Line Items]
Percentage of target retention bonus to be paid upon merger failure or abandonment	50.00%
Special charges (credits)	$ 15,563	$ (176,938)
Merger Agreement
Unusual or Infrequent Item, or Both [Line Items]
Legal, advisory and other fees	11,100
Retention bonus recorded	$ 4,500
Payroll Support Program 2
Unusual or Infrequent Item, or Both [Line Items]
Special charges (credits)		(156,500)
Severance costs and costs for voluntary separations		800
CARES Act Employee Retention Credit
Unusual or Infrequent Item, or Both [Line Items]
Special charges (credits)		$ (21,300)

Loss per Share (Details)

Loss per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Numerator
Net loss	$ (194,703)	$ (112,321)
Denominator
Weighted-average shares outstanding, basic (in shares)	108,581	97,775
Effect of dilutive shares (in shares)	0	0
Adjusted weighted-average shares outstanding, diluted (in shares)	108,581	97,775
Loss per share
Basic loss per share (in dollars per share)	$ (1.79)	$ (1.15)
Diluted loss per share (in dollars per share)	$ (1.79)	$ (1.15)

Short-term Investment Securit_2

Short-term Investment Securities (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Short-term investment securities	$ 106,013,000		$ 106,313,000
Realized gain (loss) on available-for-sale securities	0	$ 0
Accumulated other comprehensive loss	(762,000)		(532,000)
Available-for-sale Securities
Debt Securities, Available-for-sale [Line Items]
Short-term investment securities	$ 106,000,000		106,300,000
Weighted-average fixed rate	0.20%
Unrealized gain (loss) on investment securities, net of deferred taxes	$ (262,000)	7,000
Deferred taxes on unrealized gain (loss) on investment securities	(77,000)	$ 2,000
Accumulated other comprehensive loss	$ 305,000		$ 43,000

Accrued Liabilities (Details)

Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Payables and Accruals [Abstract]
Salaries, wages and benefits	$ 140,017	$ 142,893
Federal excise and other passenger taxes and fees payable	122,107	77,409
Airport obligations	94,505	85,772
Fuel	62,355	55,103
Aircraft maintenance	46,768	39,178
Interest payable	26,080	24,526
Aircraft and facility lease obligations	18,240	23,049
Other	36,661	32,824
Other current liabilities	$ 546,733	$ 480,754

Leases - Narrative (Details)

Leases - Narrative (Details)	3 Months Ended
	Mar. 31, 2022USD ($)aircraftaircraft_engine	Dec. 31, 2019USD ($)aresidential_building_unit
Lessee, Lease, Description [Line Items]
Number of spare engines capitalized | aircraft_engine	21
Area of land | a		8.5
Land | $		$ 41,000,000
Noncancellable short-term operating lease, payments, remainder of year | $	$ 4,500,000
Noncancellable short-term operating lease, payments, year one and beyond | $	$ 0
Aircraft
Lessee, Lease, Description [Line Items]
Failed aircraft sale leaseback	1
A320 Family | Aircraft
Lessee, Lease, Description [Line Items]
Number of aircraft held	176
Number of aircraft owned	105
Number of capitalized aircraft or engine purchased off lease	33
Aircraft
Lessee, Lease, Description [Line Items]
Number of aircraft under sale-leaseback transactions	3
Aircraft | A320 Family
Lessee, Lease, Description [Line Items]
Number of leased assets financed under operating leases	70
Aircraft | Minimum
Lessee, Lease, Description [Line Items]
Operating leases, term	8 years
Aircraft | Maximum
Lessee, Lease, Description [Line Items]
Operating leases, term	18 years
Other Leased Equipment and Property
Lessee, Lease, Description [Line Items]
Area of land | a		2.6
Number of residential building unit expected to be build | residential_building_unit		200
Other Leased Equipment and Property | Maximum
Lessee, Lease, Description [Line Items]
Operating leases, term	99 years	99 years
Spare Engines
Lessee, Lease, Description [Line Items]
Number of engines purchased with cash | aircraft_engine	1
Number of leased assets financed under operating leases | aircraft_engine	12
Leased Computer And Office Equipment | Minimum
Lessee, Lease, Description [Line Items]
Finance leases, term	4 years
Leased Computer And Office Equipment | Maximum
Lessee, Lease, Description [Line Items]
Finance leases, term	5 years

Leases - Finance and Operating

Leases - Finance and Operating Lease Maturities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Finance Leases
Remainder of 2022	$ 631
2023	465
2024	215
2025	117
2026	39
2027 and thereafter	0
Total minimum lease payments	1,467
Less amount representing interest	72
Present value of minimum lease payments	1,395
Less current portion	761
Long-term portion	634
Operating Leases
Less current portion	164,814	$ 158,631
Long-term portion	1,835,306	$ 1,751,351
Total Operating and Finance Lease Obligations
Remainder of 2022	204,649
2023	266,654
2024	252,044
2025	231,086
2026	204,520
2027 and thereafter	1,802,503
Total minimum lease payments	2,961,456
Less amount representing interest	959,941
Present value of minimum lease payments	2,001,515
Less current portion	165,575
Long-term portion	$ 1,835,940
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Long-term Debt and Lease Obligation, Including Current Maturities	Long-term Debt and Lease Obligation, Including Current Maturities
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Current maturities of long-term debt, net and finance leases	Current maturities of long-term debt, net and finance leases
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Long-term debt, net and finance leases, less current maturities	Long-term debt, net and finance leases, less current maturities
Aircraft and Spare Engine Leases
Operating Leases
Remainder of 2022	$ 199,747
2023	260,628
2024	248,019
2025	229,777
2026	203,517
2027 and thereafter	1,660,329
Total minimum lease payments	2,802,017
Less amount representing interest	826,808
Present value of minimum lease payments	1,975,209
Less current portion	160,378
Long-term portion	1,814,831
Property Facility Leases
Operating Leases
Remainder of 2022	4,153
2023	5,548
2024	3,810
2025	1,192
2026	964
2027 and thereafter	142,174
Total minimum lease payments	157,841
Less amount representing interest	133,060
Present value of minimum lease payments	24,781
Less current portion	4,306
Long-term portion	20,475
Other
Operating Leases
Remainder of 2022	118
2023	13
2024	0
2025	0
2026	0
2027 and thereafter	0
Total minimum lease payments	131
Less amount representing interest	1
Present value of minimum lease payments	130
Less current portion	130
Long-term portion	$ 0

Leases - Lease Costs (Details)

Leases - Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Finance lease cost
Amortization of leased assets	$ 188	$ 168
Interest of lease liabilities	18	24
Operating lease cost
Operating lease cost	63,251	52,141
Short-term lease cost	10,257	7,015
Variable lease cost	48,694	38,149
Total lease cost	$ 122,408	$ 97,497

Leases - Weighted Average Lease

Leases - Weighted Average Lease Terms and Discount Rates (Details)	Mar. 31, 2022	Mar. 31, 2021
Weighted-average remaining lease term
Operating leases	14 years	13 years 2 months 12 days
Finance leases	2 years 3 months 18 days	2 years 4 months 24 days
Weighted-average discount rate
Operating leases	5.62%	6.06%
Finance leases	4.71%	5.52%

Commitments and Contingencies -

Commitments and Contingencies - Aircraft-Related Commitments and Financing Arrangements (Details) $ in Millions	Mar. 31, 2022USD ($)aircraftaircraft_engine	Aug. 31, 2020
Aircraft-Related Secured Debt
Interest Commitments
Interest commitments, remainder of fiscal year	$ 56.7
Interest commitments, 2023	64.6
Interest commitments, 2024	53.3
Interest commitments, 2025	45.8
Interest commitments, 2026	38.3
Interest commitments, 2027 and thereafter	$ 90.3
Secured Debt | 8.00% Senior Secured Notes Due 2025
Interest Commitments
Stated interest rate percentage	8.00%	8.00%
Non-Aircraft-Related Secured Debt, Unsecured Debt And Convertible Debt
Interest Commitments
Interest commitments, remainder of fiscal year	$ 37.9
Interest commitments, 2023	48.5
Interest commitments, 2024	48.5
Interest commitments, 2025	45.5
Interest commitments, 2026	5.9
Interest commitments, 2027 and thereafter	$ 14
A320 and A321
Aircraft Rent Commitments For Future Aircraft Deliveries
Number of delivered aircraft with secured debt financing commitments | aircraft	73
Aircraft and Related Flight Equipment
Committed Expenditures
Committed expenditures, remainder of fiscal year	$ 727.3
Committed expenditures, 2023	906.9
Committed expenditures, 2024	999.4
Committed expenditures, 2025	1,060.7
Committed expenditures, 2026	1,349.9
Committed expenditures, 2027 and thereafter	872.8
Non-aircraft Related Commitments
Committed Expenditures
Committed expenditures, remainder of fiscal year	29.6
Committed expenditures, 2023	21.1
Committed expenditures, 2024	17.4
Committed expenditures, 2025	17.4
Committed expenditures, 2026	16.8
Committed expenditures, 2027 and thereafter	$ 18.8
PurePower PW1100G-JM Engine
Unrecorded Unconditional Purchase Obligation [Line Items]
Number of spare aircraft engines ordered | aircraft_engine	15
Airbus
Unrecorded Unconditional Purchase Obligation [Line Items]
Future aircraft to be received | aircraft	117
Number of aircraft to be delivered, remainder of fiscal year | aircraft	14
Number of aircraft to be delivered, 2023 | aircraft	17
Airbus | 2021 through 2022
Committed Expenditures
Number of aircraft with secured debt financing commitments scheduled for delivery | aircraft	14
Airbus | Through 2027
Committed Expenditures
Number of aircraft without secured financing commitments scheduled for delivery | aircraft	103
Third Party Lessor | A320 Family
Aircraft Rent Commitments For Future Aircraft Deliveries
Operating lease payments expected for aircraft to be delivered, remainder of fiscal year	$ 30.2
Operating lease payments expected for aircraft to be delivered, 2023	124.9
Operating lease payments expected for aircraft to be delivered, 2024	202.3
Operating lease payments expected for aircraft to be delivered, 2025	231.2
Operating lease payments expected for aircraft to be delivered, 2026	231.2
Operating lease payments expected for aircraft to be delivered, 2027 and thereafter	$ 1,954.2
Third Party Lessor | 2022 Through 2024 | A320 and A321
Unrecorded Unconditional Purchase Obligation [Line Items]
Future aircraft to be received | aircraft	40

Commitments and Contingencies_2

Commitments and Contingencies - Litigation and Assessments And Credit Card Processing Arrangements (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Restricted Cash and Cash Equivalents Items [Line Items]
Internal revenue service assessment received for amount related to the collection of federal excise taxes	$ 34,900,000
Recognized a loss contingency	0
Maximum potential exposure to cash holdbacks from credit card processors	632,600,000	$ 371,800,000
Credit Card Holdbacks
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash holdbacks	$ 0	$ 0

Commitments and Contingencies_3

Commitments and Contingencies - Employees (Details) - employeeGroup	Feb. 21, 2022	Mar. 31, 2022
Transport Workers Union of America ("TWU")
Concentration Risk [Line Items]
Collective bargaining arrangement, term	5 years
Unionized Employees Concentration Risk | Number of Employees, Total
Concentration Risk [Line Items]
Number of union-represented employee groups		5
Company's employees covered under collective bargaining agreements percentage		80.00%
Unionized Employees Concentration Risk | Number of Employees, Total | Air Line Pilots Association, International ("ALPA")
Concentration Risk [Line Items]
Company's employees covered under collective bargaining agreements percentage		27.00%
Unionized Employees Concentration Risk | Number of Employees, Total | Association of Flight Attendants ("AFA-CWA")
Concentration Risk [Line Items]
Company's employees covered under collective bargaining agreements percentage		47.00%
Unionized Employees Concentration Risk | Number of Employees, Total | Professional Airline Flight Control Association ("PAFCA")
Concentration Risk [Line Items]
Company's employees covered under collective bargaining agreements percentage		1.00%
Unionized Employees Concentration Risk | Number of Employees, Total | International Association of Machinists and Aerospace Workers ("IAMAW")
Concentration Risk [Line Items]
Company's employees covered under collective bargaining agreements percentage		3.00%
Unionized Employees Concentration Risk | Number of Employees, Total | Transport Workers Union of America ("TWU")
Concentration Risk [Line Items]
Company's employees covered under collective bargaining agreements percentage		2.00%

Fair Value Measurements - Long-

Fair Value Measurements - Long-term Debt (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Aug. 31, 2020	May 12, 2020
Debt Instrument [Line Items]
Carrying Value	$ 3,193.8	$ 3,238.2
Secured Debt | 8.00% senior secured notes
Debt Instrument [Line Items]
Stated interest rate percentage	8.00%		8.00%
Carrying Value	$ 510	510
Fixed-rate term loans
Debt Instrument [Line Items]
Carrying Value	1,190.9	1,223.5
Unsecured term loans | Payroll Support Program, CARES Act
Debt Instrument [Line Items]
Carrying Value	136.3	136.3
2015-1 EETC Class A
Debt Instrument [Line Items]
Carrying Value	300.6	300.6
2015-1 EETC Class B
Debt Instrument [Line Items]
Carrying Value	56	56
2015-1 EETC Class C
Debt Instrument [Line Items]
Carrying Value	75.2	75.2
2017-1 EETC Class AA
Debt Instrument [Line Items]
Carrying Value	193.3	200.3
2017-1 EETC Class A
Debt Instrument [Line Items]
Carrying Value	64.4	66.8
2017-1 EETC Class B
Debt Instrument [Line Items]
Carrying Value	53.4	55.8
2017-1 EETC Class C
Debt Instrument [Line Items]
Carrying Value	$ 85.5	85.5
Convertible notes | 4.75% convertible notes due 2025
Debt Instrument [Line Items]
Stated interest rate percentage	4.75%			4.75%
Carrying Value	$ 28.2	28.2
Convertible notes | 1.00% convertible notes due 2026
Debt Instrument [Line Items]
Stated interest rate percentage	1.00%
Carrying Value	$ 500	500
Estimated Fair Value
Debt Instrument [Line Items]
Estimated Fair Value	3,110.1	3,275.8
Estimated Fair Value | Level 3 | Secured Debt | 8.00% senior secured notes
Debt Instrument [Line Items]
Estimated Fair Value	504.8	530.4
Estimated Fair Value | Level 3 | Fixed-rate term loans
Debt Instrument [Line Items]
Estimated Fair Value	1,168.7	1,262.6
Estimated Fair Value | Level 3 | Unsecured term loans | Payroll Support Program, CARES Act
Debt Instrument [Line Items]
Estimated Fair Value	132.7	146.4
Estimated Fair Value | Level 2 | 2015-1 EETC Class A
Debt Instrument [Line Items]
Estimated Fair Value	294	311.1
Estimated Fair Value | Level 2 | 2015-1 EETC Class B
Debt Instrument [Line Items]
Estimated Fair Value	54.9	56.4
Estimated Fair Value | Level 2 | 2015-1 EETC Class C
Debt Instrument [Line Items]
Estimated Fair Value	73.3	74
Estimated Fair Value | Level 2 | 2017-1 EETC Class AA
Debt Instrument [Line Items]
Estimated Fair Value	184.8	203.3
Estimated Fair Value | Level 2 | 2017-1 EETC Class A
Debt Instrument [Line Items]
Estimated Fair Value	60.4	65.8
Estimated Fair Value | Level 2 | 2017-1 EETC Class B
Debt Instrument [Line Items]
Estimated Fair Value	48.9	53.6
Estimated Fair Value | Level 2 | 2017-1 EETC Class C
Debt Instrument [Line Items]
Estimated Fair Value	83.5	84.1
Estimated Fair Value | Level 2 | Convertible notes | 4.75% convertible notes due 2025
Debt Instrument [Line Items]
Estimated Fair Value	55.7	55.6
Estimated Fair Value | Level 2 | Convertible notes | 1.00% convertible notes due 2026
Debt Instrument [Line Items]
Estimated Fair Value	$ 448.4	$ 432.5

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2022	Feb. 05, 2022	Aug. 31, 2020
Control Agreements For Interest And Fee Payments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Restricted cash	$ 20.4
Secured Debt | 8.00% Senior Secured Notes Due 2025
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate percentage	8.00%		8.00%
Convertible notes | 1.00% convertible notes due 2026
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate percentage	1.00%
Fair value of the embedded derivative		$ 49.5
Standby Letters of Credit | Secured Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Letters of credit, limit, amount	$ 85
Restricted cash	75
Letter of credit facility, amount outstanding	$ 27

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured on Recurring Basis (Details) - Fair Value, Recurring - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 1,247.9	$ 1,333.5
Restricted cash	95.4	95.4
Short-term investment securities	106	106.3
Assets held for sale	2.5	2.5
Total assets	1,451.8	1,537.7
Derivative liability	48.6
Total liabilities	48.6	0
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	1,247.9	1,333.5
Restricted cash	95.4	95.4
Short-term investment securities	106	106.3
Assets held for sale	0	0
Total assets	1,449.3	1,535.2
Derivative liability	0
Total liabilities	0	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Restricted cash	0	0
Short-term investment securities	0	0
Assets held for sale	0	0
Total assets	0	0
Derivative liability	48.6
Total liabilities	48.6	0
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Restricted cash	0	0
Short-term investment securities	0	0
Assets held for sale	2.5	2.5
Total assets	2.5	2.5
Derivative liability	0
Total liabilities	$ 0	$ 0

Debt and Other Obligations - Na

Debt and Other Obligations - Narrative (Details)	Apr. 30, 2021USD ($)day$ / sharesshares	May 12, 2020USD ($)day$ / sharesshares	Mar. 31, 2022USD ($)	Mar. 31, 2021USD ($)	Feb. 05, 2022USD ($)	Dec. 31, 2021USD ($)	Jun. 30, 2020USD ($)	Mar. 30, 2020USD ($)
Debt Instrument [Line Items]
Long-term debt			$ 3,193,800,000			$ 3,238,200,000
Long-term debt and capital leases, less current maturities			2,801,200,000			2,975,100,000
Less unamortized discounts, net			99,400,000			54,900,000
Repayments of long-term debt			$ 44,300,000	$ 135,900,000
Convertible notes due 2025 | Convertible notes
Debt Instrument [Line Items]
Principal amount		$ 175,000,000
Stated interest rate percentage		4.75%	4.75%
Debt instrument, convertible, liquidation preference, during period, value			$ 22,400,000
Long-term debt			28,200,000			28,200,000
Convertible debt, conversion price threshold		130.00%
Number of trading days required for conversion price threshold | day		20
Number of consecutive days required for trading days for conversion price threshold | day		30
Number of consecutive business days for conversion price threshold | day		5
Number of consecutive trading days measurement period | day		5
Trading price threshold per principal amount portion		98.00%
Notes converted amount			$ 0
Shares conversion rate per portion of principal amount (in shares) | shares		78.4314
Principal amount portion for trading price threshold		$ 1,000
Conversion price (in dollars per share) | $ / shares		$ 12.75
1.00% convertible notes due 2026 | Convertible notes
Debt Instrument [Line Items]
Principal amount	$ 500,000,000
Stated interest rate percentage			1.00%
Long-term debt			$ 500,000,000			500,000,000
Convertible debt, conversion price threshold	130.00%
Number of trading days required for conversion price threshold | day	20
Number of consecutive days required for trading days for conversion price threshold | day	30
Number of consecutive business days for conversion price threshold | day	5
Trading price threshold per principal amount portion	98.00%
Shares conversion rate per portion of principal amount (in shares) | shares	20.3791
Principal amount portion for trading price threshold	$ 1,000
Conversion price (in dollars per share) | $ / shares	$ 49.07
Number of trading days before maturity redemption allowed | day	40
Minimum aggregate principal amount outstanding required for redemption	$ 150,000,000
Fair value of the embedded derivative					$ 49,500,000
Derivative liability adjustment			(900,000)
Long-term debt and capital leases, less current maturities			453,000,000
Less unamortized discounts, net			47,000,000
Revolving credit facilities | Revolving credit facility due in 2024 | Line of Credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity				$ 240,000,000			$ 180,000,000	$ 110,000,000
Line of credit facility, optional maximum borrowing capacity subject to consent of lenders								$ 350,000,000
Line of credit facility, remaining borrowing capacity			$ 240,000,000			$ 240,000,000
Term				2 years

Debt and Other Obligations - Sc

Debt and Other Obligations - Schedule of Long-term Debt (Details) $ in Millions	Mar. 31, 2022USD ($)aircraft	Dec. 31, 2021USD ($)	Aug. 31, 2020	May 12, 2020
Debt Instrument [Line Items]
Long-term debt	$ 3,193.8	$ 3,238.2
Less current maturities	293.2	208.2
Less unamortized discounts, net	99.4	54.9
Long-term debt and capital leases, less current maturities	$ 2,801.2	2,975.1
Aircraft
Debt Instrument [Line Items]
Failed aircraft sale leaseback | aircraft	1
8.00% senior secured notes due 2025 | 8.00% Senior Secured Notes Due 2025
Debt Instrument [Line Items]
Stated interest rate percentage	8.00%		8.00%
Long-term debt	$ 510	$ 510
Weighted-average interest rate	8.00%	8.00%
Fixed-rate loans due through 2039
Debt Instrument [Line Items]
Long-term debt	$ 1,190.9	$ 1,223.5
Weighted-average interest rate	3.52%	3.52%
Unsecured term loans due in 2031 | Payroll Support Program, CARES Act
Debt Instrument [Line Items]
Long-term debt	$ 136.3	$ 136.3
Weighted-average interest rate	1.00%	1.00%
Fixed-rate class A 2015-1 EETC due through 2028
Debt Instrument [Line Items]
Long-term debt	$ 300.6	$ 300.6
Weighted-average interest rate	4.10%	4.10%
Fixed-rate class B 2015-1 EETC due through 2024
Debt Instrument [Line Items]
Long-term debt	$ 56	$ 56
Weighted-average interest rate	4.45%	4.45%
Fixed-rate class C 2015-1 EETC due through 2023
Debt Instrument [Line Items]
Long-term debt	$ 75.2	$ 75.2
Weighted-average interest rate	4.93%	4.93%
Fixed-rate class AA 2017-1 EETC due through 2030
Debt Instrument [Line Items]
Long-term debt	$ 193.3	$ 200.3
Weighted-average interest rate	3.38%	3.38%
Fixed-rate class A 2017-1 EETC due through 2030
Debt Instrument [Line Items]
Long-term debt	$ 64.4	$ 66.8
Weighted-average interest rate	3.65%	3.65%
Fixed-rate class B 2017-1 EETC due through 2026
Debt Instrument [Line Items]
Long-term debt	$ 53.4	$ 55.8
Weighted-average interest rate	3.80%	3.80%
Fixed-rate class C 2017-1 EETC due through 2023
Debt Instrument [Line Items]
Long-term debt	$ 85.5	$ 85.5
Weighted-average interest rate	5.11%	5.11%
Convertible notes | Convertible notes due 2025
Debt Instrument [Line Items]
Stated interest rate percentage	4.75%			4.75%
Long-term debt	$ 28.2	$ 28.2
Weighted-average interest rate	4.75%	4.75%
Convertible notes | Convertible notes due 2026
Debt Instrument [Line Items]
Long-term debt	$ 500
Weighted-average interest rate	1.00%	1.00%

Debt and Other Obligations - Fu

Debt and Other Obligations - Future Maturities (Details) $ in Millions	Mar. 31, 2022USD ($)
Debt Disclosure [Abstract]
remainder of 2022	$ 148.7
2023	336.6
2024	222.1
2025	726.6
2026	731.1
2027 and beyond	1,028.7
Total debt principal payments	$ 3,193.8

Debt and Other Obligations - In

Debt and Other Obligations - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Aug. 31, 2020
Debt Instrument [Line Items]
Commitment and other fees	$ 535	$ 428
Amortization of deferred financing costs	4,222	3,509
Total	37,880	44,806
Accretion expense	261	434
Amortization of debt discount	2,538	0
8.00% senior secured notes due 2025
Debt Instrument [Line Items]
Accretion expense	300	400
Interest expense	$ 10,200	17,000
8.00% senior secured notes due 2025 | 8.00% Senior Secured Notes Due 2025
Debt Instrument [Line Items]
Stated interest rate percentage	8.00%		8.00%
Interest expense	$ 10,461	17,434
Fixed-rate term loans
Debt Instrument [Line Items]
Interest expense	10,684	10,903
Unsecured term loans | Payroll Support Program, CARES Act
Debt Instrument [Line Items]
Interest expense	336	199
Class A 2015-1 EETC
Debt Instrument [Line Items]
Interest expense	3,048	3,275
Class B 2015-1 EETC
Debt Instrument [Line Items]
Interest expense	616	705
Class C 2015-1 EETC
Debt Instrument [Line Items]
Interest expense	917	1,056
Class AA 2017-1 EETC
Debt Instrument [Line Items]
Interest expense	1,638	1,755
Class A 2017-1 EETC
Debt Instrument [Line Items]
Interest expense	590	633
Class B 2017-1 EETC
Debt Instrument [Line Items]
Interest expense	512	557
Class C 2017-1 EETC
Debt Instrument [Line Items]
Interest expense	1,080	1,080
Convertible notes
Debt Instrument [Line Items]
Interest expense	3,223	2,078
Convertible notes | Convertible Debt Due In 2025 And 2026
Debt Instrument [Line Items]
Interest expense	1,600
Convertible notes | Convertible notes due 2026
Debt Instrument [Line Items]
Amortization of debt discount	2,500
Offset of market-to-market adjustment	900
Convertible notes | Convertible Debt Due in 2025
Debt Instrument [Line Items]
Interest expense		2,100
Revolving credit facilities
Debt Instrument [Line Items]
Interest expense	0	1,170
Finance leases
Debt Instrument [Line Items]
Interest expense	$ 18	$ 24

Uncategorized Items - save-2022

Label	Element	Value
Accounting Standards Update [Extensible Enumeration]	us-gaap_AccountingStandardsUpdateExtensibleList	Accounting Standards Update 2020-06 [Member]