Frontier (ULCC) 10-Q 10 Nov 21 2021 Q3 Quarterly report Financial data

Cover

Cover - shares	9 Months Ended
	Sep. 30, 2021	Nov. 05, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	001-40304
Entity Registrant Name	Frontier Group Holdings, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-3681866
Entity Address, Address Line One	4545 Airport Way
Entity Address, City or Town	Denver
Entity Address, State or Province	CO
Entity Address, Postal Zip Code	80239
City Area Code	720
Local Phone Number	374-4200
Title of 12(b) Security	Common Stock, $0.001 par value
Trading Symbol	ULCC
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		216,012,632
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001670076
Current Fiscal Year End Date	--12-31

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Current Assets
Cash and cash equivalents	$ 802	$ 378
Accounts receivable, net	49	28
Supplies, net	29	18
Other current assets	212	226
Total current assets	1,092	650
Property and equipment, net	187	176
Operating lease right-of-use assets	2,491	2,250
Pre-delivery deposits for flight equipment	196	224
Aircraft maintenance deposits	92	82
Intangible assets, net	29	29
Other assets	165	143
Total assets	4,252	3,554
Liabilities and stockholders’ equity
Accounts payable	90	71
Air traffic liability	252	135
Frequent flyer liability	12	13
Current maturities of long-term debt, net	85	101
Current maturities of operating leases	450	416
Other current liabilities	349	267
Total current liabilities	1,238	1,003
Long-term debt, net	280	247
Long-term operating leases	2,053	1,848
Long-term frequent flyer liability	43	50
Other long-term liabilities	62	96
Total liabilities	3,676	3,244
Commitments and contingencies
Stockholders' equity
Common stock, $0.001 par value per share, with 215,474,482 and 199,438,098 shares issued and outstanding as of September 30, 2021 and December 31, 2020, respectively	0	0
Additional paid-in capital	374	60
Retained earnings	212	261
Accumulated other comprehensive income (loss)	(10)	(11)
Total stockholders’ equity	576	310
Total liabilities and stockholders’ equity	$ 4,252	$ 3,554

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Common stock, stated par (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares issued (in shares)	215,474,482	199,438,098
Common stock outstanding (in shares)	215,474,482	199,438,098

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Operating revenues:
Total operating revenues	$ 630,000	$ 245,000	$ 1,451,000	$ 983,000
Operating expenses:
Aircraft fuel	166,000	62,000	389,000	281,000
Salaries, wages and benefits	161,000	128,000	454,000	406,000
Aircraft rent	128,000	115,000	399,000	266,000
Station operations	108,000	63,000	285,000	182,000
Sales and marketing	33,000	17,000	80,000	62,000
Maintenance materials and repairs	29,000	17,000	82,000	59,000
Depreciation and amortization	10,000	8,000	28,000	23,000
CARES Act credits	(72,000)	(97,000)	(295,000)	(188,000)
Other operating	24,000	13,000	60,000	73,000
Total operating expenses	587,000	326,000	1,482,000	1,164,000
Operating income (loss)	43,000	(81,000)	(31,000)	(181,000)
Other income (expense):
Interest expense	(4,000)	(2,000)	(31,000)	(7,000)
Capitalized interest	1,000	1,000	3,000	5,000
Interest income and other	1,000	0	1,000	4,000
Total other income (expense)	(2,000)	(1,000)	(27,000)	2,000
Income (loss) before income taxes	41,000	(82,000)	(58,000)	(179,000)
Income tax expense (benefit)	18,000	(31,000)	(9,000)	(81,000)
Net income (loss)	$ 23,000	$ (51,000)	$ (49,000)	$ (98,000)
Earnings (loss) per share:
Basic (in dollars per share)	$ 0.10	$ (0.26)	$ (0.23)	$ (0.49)
Diluted (in dollars per share)	$ 0.10	$ (0.26)	$ (0.23)	$ (0.49)
Passenger
Operating revenues:
Total operating revenues	$ 610,000	$ 237,000	$ 1,408,000	$ 950,000
Other
Operating revenues:
Total operating revenues	$ 20,000	$ 8,000	$ 43,000	$ 33,000

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 23,000	$ (51,000)	$ (49,000)	$ (98,000)
Other comprehensive loss
Unrealized gains (losses) and amortization from cash flow hedges net of adjustment for de-designation of fuel hedges, net of deferred tax benefit/(expense)	0	7,000	1,000	(17,000)
Other comprehensive income (loss)	0	7,000	1,000	(17,000)
Comprehensive income (loss)	$ 23,000	$ (44,000)	$ (48,000)	$ (115,000)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($)	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net loss	$ (49,000,000)	$ (98,000,000)
Deferred income taxes	(9,000,000)	(9,000,000)
Depreciation and amortization	28,000,000	23,000,000
Gains recognized on sale-leaseback transactions	(55,000,000)	(37,000,000)
Warrant liability unrealized loss	22,000,000	1,000,000
Stock-based compensation	8,000,000	6,000,000
Amortization of swaption cash flow hedges, net of tax	1,000,000	0
Cash flows for derivative instruments, net	0	(6,000,000)
Cash flows from operating leases	0	17,000,000
Changes in operating assets and liabilities:
Accounts receivable	(15,000,000)	47,000,000
Supplies and other current assets	13,000,000	(104,000,000)
Aircraft maintenance deposits	(14,000,000)	(12,000,000)
Other long-term assets	(24,000,000)	(34,000,000)
Accounts payable	16,000,000	36,000,000
Air traffic liability	117,000,000	(86,000,000)
Other liabilities	57,000,000	(110,000,000)
Cash provided by (used in) operating activities	96,000,000	(366,000,000)
Cash flows from investing activities:
Capital expenditures	(20,000,000)	(6,000,000)
Pre-delivery deposits for flight equipment, net of refunds	28,000,000	22,000,000
Other	(4,000,000)	(1,000,000)
Cash provided by investing activities	4,000,000	15,000,000
Cash flows from financing activities:
Proceeds from issuance of debt	115,000,000	226,000,000
Principal repayments on debt	(97,000,000)	(111,000,000)
Proceeds from sale-leaseback transactions	43,000,000	34,000,000
Proceeds from initial public offering, net of offering costs and underwriting discounts	266,000,000	0
Minimum tax withholdings on share-based awards	(3,000,000)	(1,000,000)
Cash provided by financing activities	324,000,000	148,000,000
Net increase (decrease) in cash, cash equivalents and restricted cash	424,000,000	(203,000,000)
Cash, cash equivalents and restricted cash, beginning of period	378,000,000	768,000,000
Cash, cash equivalents and restricted cash, end of period	$ 802,000,000	$ 565,000,000

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Stockholders’ Equity - USD ($) $ in Thousands	Total	Common Stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income (loss)
Beginning balance (in shares) at Dec. 31, 2019		199,242,854
Beginning balance at Dec. 31, 2019	$ 542,000	$ 0	$ 52,000	$ 486,000	$ 4,000
Net income (loss)	(64,000)			(64,000)
Unrealized gains (losses) and amortization from cash flow hedges net of adjustment for de-designation of fuel hedges, net of deferred tax benefit/(expense)	(26,000)				(26,000)
Stock-based compensation	2,000		2,000
Ending balance (in shares) at Mar. 31, 2020		199,242,854
Ending balance at Mar. 31, 2020	454,000	$ 0	54,000	422,000	(22,000)
Beginning balance (in shares) at Dec. 31, 2019		199,242,854
Beginning balance at Dec. 31, 2019	542,000	$ 0	52,000	486,000	4,000
Net income (loss)	(98,000)
Unrealized gains (losses) and amortization from cash flow hedges net of adjustment for de-designation of fuel hedges, net of deferred tax benefit/(expense)	(17,000)
Ending balance (in shares) at Sep. 30, 2020		199,428,142
Ending balance at Sep. 30, 2020	433,000	$ 0	58,000	388,000	(13,000)
Beginning balance (in shares) at Mar. 31, 2020		199,242,854
Beginning balance at Mar. 31, 2020	454,000	$ 0	54,000	422,000	(22,000)
Net income (loss)	17,000			17,000
Shares issued in connection with vesting of restricted stock units (in shares)		46,892
Shares withheld to cover employee taxes on vested restricted stock units (in shares)		(13,604)
Unrealized gains (losses) and amortization from cash flow hedges net of adjustment for de-designation of fuel hedges, net of deferred tax benefit/(expense)	2,000				2,000
Stock-based compensation	2,000		2,000
Ending balance (in shares) at Jun. 30, 2020		199,276,142
Ending balance at Jun. 30, 2020	475,000	$ 0	56,000	439,000	(20,000)
Net income (loss)	(51,000)			(51,000)
Restricted stock issued (in shares)		99,408
Shares issued in connection with vesting of restricted stock units (in shares)		73,986
Shares withheld to cover employee taxes on vested restricted stock units (in shares)		(21,394)
Unrealized gains (losses) and amortization from cash flow hedges net of adjustment for de-designation of fuel hedges, net of deferred tax benefit/(expense)	7,000				7,000
Stock-based compensation	2,000		2,000
Ending balance (in shares) at Sep. 30, 2020		199,428,142
Ending balance at Sep. 30, 2020	$ 433,000	$ 0	58,000	388,000	(13,000)
Beginning balance (in shares) at Dec. 31, 2020	199,438,098	199,438,098
Beginning balance at Dec. 31, 2020	$ 310,000	$ 0	60,000	261,000	(11,000)
Net income (loss)	(91,000)			(91,000)
Shares issued in connection with vesting of restricted stock units (in shares)		505,438
Shares withheld to cover employee taxes on vested restricted stock units (in shares)		(146,490)
Shares withheld to cover employee taxes on vested restricted stock units	(3,000)		(3,000)
Restricted stock unit repurchases (in shares)		(20,368)
Stock option exercise (in shares)		640,121
Stock-based compensation	3,000		3,000
Ending balance (in shares) at Mar. 31, 2021		200,416,799
Ending balance at Mar. 31, 2021	$ 219,000	$ 0	60,000	170,000	(11,000)
Beginning balance (in shares) at Dec. 31, 2020	199,438,098	199,438,098
Beginning balance at Dec. 31, 2020	$ 310,000	$ 0	60,000	261,000	(11,000)
Net income (loss)	(49,000)
Unrealized gains (losses) and amortization from cash flow hedges net of adjustment for de-designation of fuel hedges, net of deferred tax benefit/(expense)	$ 1,000
Stock option exercise (in shares)	645,966
Ending balance (in shares) at Sep. 30, 2021	215,474,482	215,474,482
Ending balance at Sep. 30, 2021	$ 576,000	$ 0	374,000	212,000	(10,000)
Beginning balance (in shares) at Mar. 31, 2021		200,416,799
Beginning balance at Mar. 31, 2021	219,000	$ 0	60,000	170,000	(11,000)
Net income (loss)	19,000			19,000
Shares issued in connection with vesting of restricted stock units (in shares)		18,259
Shares withheld to cover employee taxes on vested restricted stock units (in shares)		(8,015)
Unrealized gains (losses) and amortization from cash flow hedges net of adjustment for de-designation of fuel hedges, net of deferred tax benefit/(expense)	1,000				1,000
Issuance of common stock upon initial public offering, net of offering costs, underwriting discounts and commissions (in shares)		15,000,000
Issuance of common stock upon initial public offering, net of offering costs, underwriting discounts and commissions	266,000		266,000
Payroll Support Program warrants	43,000		43,000
Stock-based compensation	2,000		2,000
Ending balance (in shares) at Jun. 30, 2021		215,427,043
Ending balance at Jun. 30, 2021	550,000	$ 0	371,000	189,000	(10,000)
Net income (loss)	23,000			23,000
Shares issued in connection with vesting of restricted stock units (in shares)		74,140
Shares withheld to cover employee taxes on vested restricted stock units (in shares)		(32,546)
Unrealized gains (losses) and amortization from cash flow hedges net of adjustment for de-designation of fuel hedges, net of deferred tax benefit/(expense)	0
Stock option exercise (in shares)		5,845
Stock-based compensation	$ 3,000		3,000
Ending balance (in shares) at Sep. 30, 2021	215,474,482	215,474,482
Ending balance at Sep. 30, 2021	$ 576,000	$ 0	$ 374,000	$ 212,000	$ (10,000)

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Unrealized losses from cash flow hedges net of adjustment for de-designation of fuel hedges, tax benefit/(expense)	$ (1)	$ (4)	$ (1)	$ 5

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The condensed consolidated financial statements have been prepared in accordance with the accounting principles generally accepted in the United States (“GAAP”) and include the accounts of Frontier Group Holdings, Inc. (“FGHI” or the “Company”) and its wholly-owned direct and indirect subsidiaries, including Frontier Airlines Holdings, Inc. (“FAH”) and Frontier Airlines, Inc. (“Frontier”). All wholly-owned subsidiaries are consolidated, with all intercompany transactions and balances being eliminated. The Company is headquartered in Denver, Colorado. Frontier is an ultra low-cost, low-fare airline that offers flights throughout the United States and to select international destinations in the Americas, serving approximately 120 airports. The Company is managed as a single business unit that primarily provides air transportation for passengers. Management has concluded there is only one reportable segment. The accompanying condensed consolidated financial statements include the accounts of the Company and 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 annual financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) 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 final prospectus, dated March 31, 2021, and filed with the SEC pursuant to Rule 424(b) on April 2, 2021. The interim results reflected in the unaudited condensed consolidated financial statements are not necessarily indicative of the results that may be expected for other interim periods or for the full year. The air transportation business is subject to significant seasonal fluctuations and is volatile and highly affected by economic cycles and trends. In addition, the Company experienced significant impacts from the novel strain of coronavirus (“COVID-19”) pandemic during the three and nine months ended September 30, 2021, as well as during the comparable periods in 2020. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities in the financial statements and accompanying notes. Actual results could differ from those estimates. Initial Public Offering On March 31, 2021, the Company’s registration statement on Form S-1 relating to the Company’s initial public offering (“IPO”) was declared effective by the SEC, and the Company’s common stock began trading on the NASDAQ Global Select Market on April 1, 2021 under the symbol “ULCC”. The Company completed its IPO on April 6, 2021 at an offering price of $19.00 per share, pursuant to the Company’s registration statement. The Company issued and sold 15 million shares of common stock and the Company’s selling stockholders sold 15 million shares of common stock in the IPO . The underwriters were granted an over-allotment option to purchase up to 4.5 million additional shares of common stock from the selling shareholders, at the IPO price of $19.00 per share, less the underwriting discount, for 30 days from the date of the prospectus, which was exercised in full in April 2021. T he Company did not receive any of the proceeds from the sale of shares by the Company’s selling stockholders. In April 2021, the Company received net proceeds of $266 million after deducting underwriting discounts and commissions of $14 million and offering costs of $5 million, which consisted of direct incremental legal, accounting, consulting and other fees relating to the IPO. Recently Adopted Accounting Pronouncements In December 2019, the FASB issued ASU 2019-12, Simplifying the Accounting for Income Taxes (“ASU 2019-12”). ASU 2019-12 simplifies the accounting for income taxes by removing certain exceptions to the general principles in Topic 740 and also enhances the existing guidance for consistent application of Topic 740. The new guidance is effective for annual periods beginning after December 15, 2020 and interim reporting periods within those reporting periods. The Company adopted the new standard as of January 1, 2021, which did not have a material impact on the Company’s results of operations or financial position as of the adoption date. In August 2020, the FASB issued ASU 2020-06, Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity (“ASU 2020-06”). ASU 2020-06 simplifies the accounting and measurement of convertible instruments and also adds disclosure requirements. Further, ASU 2020-06 simplifies the settlement assessment performed to determine whether a contract in the Company’s own equity qualifies for equity classification. The Company early adopted the standard effective January 1, 2021 using the modified retrospective approach, which did not have a material impact on the Company’s results of operations or financial position as of the adoption date. Given the Company’s IPO in April 2021, and based in part on the provisions of ASU 2020-06, warrants issued in conjunction with the CARES Act that may be settled in the Company’s own equity if publicly traded, were classified into equity during the second quarter of 2021.

Impact of COVID-19

Impact of COVID-19	9 Months Ended
	Sep. 30, 2021
Unusual or Infrequent Items, or Both [Abstract]
Impact of COVID-19	Impact of COVID-19 Impact of the COVID-19 Pandemic Beginning in March 2020, the rapid spread of COVID-19, along with government-mandated restrictions on travel, required stay-in-place orders, and other social distancing measures, resulted in a drastic decline in near-term air travel demand in the United States, and caused reductions in revenues and income levels as compared to corresponding pre-pandemic periods. The decline in demand for air travel has had a material adverse effect on the Company’s business and results of operations for the three and nine months ended September 30, 2021 and the comparable prior year periods. Although the Company has seen significant recovery of demand through the quarter ended September 30, 2021 as compared to the corresponding prior year period, the Company is unable to predict the future spread of COVID-19, including future variants of the virus such as the recent Delta variant, as well as efficacy and adherence rates of vaccines and related boosters and the resulting measures that may be introduced by governments or other parties and what impact those measures may have on the demand for air travel. Beginning in December 2020, the Food and Drug Administration issued emergency use authorizations for various vaccines for COVID-19. Widespread distribution of the vaccines has led to increased confidence in travel, particularly in the domestic leisure market on which the Company’s business is focused. While the Company has experienced a meaningful increase in passenger volumes as well as bookings since the vaccines became widely available, demand recovery slowed during the second half of the quarter ending September 30, 2021, due to the rise in cases from the Delta variant. The Company continues to closely monitor the COVID-19 pandemic and the need to adjust capacity and deploy other operational and cost-control measures as necessary to preserve short-term liquidity needs and ensure long-term viability of the Company and its strategies. Any anticipated adjustments to capacity and other cost savings initiatives implemented by the Company may vary from actual demand and capacity needs. The Company continues to monitor covenant compliance with various parties, including, but not limited to, its lenders and credit card processors. As of September 30, 2021 and through the date of this report, the Company is in compliance with all of its covenants, except the Company has obtained a waiver of relief for the covenant provisions through the fourth quarter of 2021 related to one of its credit card processors that represents less than 10% of total revenues, which may require future waivers or an amendment to the existing covenants to reflect any additional COVID-19 pandemic impacts. COVID-19 Relief Funding The Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”) became law on March 27, 2020 and includes various provisions to protect the U.S. airline industry, its employees, and many other stakeholders. The CARES Act is a relief package intended to assist many aspects of the American economy, including providing the airline industry with up to $25 billion for a Payroll Support Program (“PSP”) to be used for employee wages, salaries, and benefits and up to $25 billion in loans. On April 30, 2020, the Company reached an agreement with the U.S. Department of the Treasury (the “Treasury”) under which the Company received $211 million of installment funding comprised of a $178 million grant (the “PSP Grant”) for payroll support for the period from April 2020 through September 2020, and a $33 million unsecured 10-year, low-interest loan (the “PSP Promissory Note”), all of which was received as of December 31, 2020. The PSP Grant was recognized over the periods it was intended to support payroll, including $92 million net of $1 million in deferred financing costs for the three months ended September 30, 2020; and the full $178 million net of $1 million in deferred financing costs for the nine months ended September 30, 2020, within CARES Act credits in the Company’s condensed consolidated statements of operations. In conjunction with the PSP Promissory Note, the Company issued to the Treasury warrants to purchase up to 522,576 shares of common stock of FGHI at an exercise price of $6.36 per share. On January 15, 2021, as a result of the Consolidated Appropriations Act, 2021 (the “PSP Extension Law”), which extended the PSP provisions of the CARES Act, the Company entered into an agreement with the Treasury for installment funding under a second Payroll Support Program (“PSP2”), under which the Company received $161 million, comprised of a $143 million grant (the “PSP2 Grant”) for the continuation of payroll support through March 31, 2021, and an $18 million unsecured 10-year, low-interest loan (the “PSP2 Promissory Note”), all of which has been received as of September 30, 2021. The Company recognized the full $143 million PSP2 Grant, which had been fully recognized prior to the three months ended September 30, 2021, during the nine months ended September 30, 2021, net of deferred financing costs within CARES Act credits in the Company’s condensed consolidated statements of operations. In conjunction with the PSP2 Promissory Note, the Company issued to the Treasury warrants to purchase up to 157,313 shares of common stock of FGHI at an exercise price of $11.65 per share. The American Rescue Plan Act (“ARP”), enacted on March 11, 2021, provided for additional assistance to passenger air carriers that received financial relief under PSP2. On April 29, 2021, the Company entered into an agreement with the Treasury for installment funding under a third Payroll Support Program (“PSP3”), under which the Company received $150 million, comprised of a $135 million grant (the “PSP3 Grant”) for the continuation of payroll support through September 30, 2021, and a $15 million unsecured 10-year, low-interest loan (the “PSP3 Promissory Note”), all of which has been received as of September 30, 2021. Of the $135 million received under the PSP3 Grant, $72 million and the full $135 million was recognized during the three and nine months ended September 30, 2021, respectively, within CARES Act credits in the Company’s condensed consolidated statements of operations. In conjunction with the PSP3 Promissory Note, the Company issued to the Treasury warrants to purchase up to 79,961 shares of common stock of FGHI at an exercise price of $18.85 per share. On September 28, 2020, the Company entered into a loan agreement with the Treasury for a term loan facility of up to $574 million pursuant to the secured loan program established under the CARES Act (the “Treasury Loan”). In conjunction with the Treasury Loan, the Company issued to the Treasury warrants to purchase up to 2,358,090 shares of common stock of FGHI at an exercise price of $6.36 per share. As of September 30, 2021 and December 31, 2020, the Company had borrowed $150 million under the Treasury Loan, for which the right to draw any further funds lapsed in May 2021. In connection with the Company’s participation in the PSP, PSP2, PSP3 and the Treasury Loan, the Company has been and will continue to be subject to certain restrictions and limitations, including, but not limited to: • Restrictions on repurchases of equity securities listed on a national securities exchange or payment of dividends until one year after the Treasury Loan is repaid; • Requirements to maintain certain levels of scheduled services through March 31, 2022 (including to destinations where there may currently be significantly reduced or no demand); • A prohibition on involuntary terminations or furloughs of employees (except for health, disability, cause, or certain disciplinary reasons) through September 30, 2021; • A prohibition on reducing the salary, wages or benefits of employees (other than executive officers or independent contractors, or as otherwise permitted under the terms of the PSP, PSP2 and PSP3) through September 30, 2021; • Limits on certain executive compensation, including limiting pay increases and severance pay or other benefits upon terminations, until the later of April 1, 2023 or one year after the Treasury Loan is repaid; • Limitations on the use of the grant funds exclusively for the continuation of payment of employee wages, salaries and benefits; and • Additional reporting and recordkeeping requirements. As outlined above, as part of the PSP Promissory Note, the PSP2 Promissory Note, the PSP3 Promissory Note (collectively, the “PSP Promissory Notes”) and the Treasury Loan, and pursuant to the stipulations set forth within the CARES Act, the Company issued to the Treasury warrants to purchase shares of common stock of FGHI, which have a five-year term and are settled in cash or shares at the election of the Company. The warrants do not have any voting rights and are freely transferable, with registration rights. The initial fair value of these warrants upon issuance is treated as a loan discount, which reduces the carrying value of the loan, and is amortized utilizing the effective interest method as interest expense in the Company’s condensed consolidated statements of operations over the term of the loan. These awards were originally classified as liability-based awards within other current liabilities on the condensed consolidated balance sheets, with periodic mark to market remeasurements being included in interest expense given the Company only had the option of settling in cash before being publicly traded. As a result of the IPO, the Company has the intent and ability to settle the warrants issued to the Treasury in shares and as a result, as of April 6, 2021, the Company reclassified the warrant liability to additional paid-in capital on the condensed consolidated balance sheet and is no longer required to mark to market the warrants. Subsequent warrants issued after the IPO date were recorded at fair value as a reduction to the related debt they were issued with and recorded to additional paid-in capital on the condensed consolidated balance sheet. The Company recorded $22 million in mark to market adjustments during the nine months ended September 30, 2021, and $1 million during each of the three and nine months ended September 30, 2020, to interest expense within the Company’s condensed consolidated statements of operations. The CARES Act also provided for an employee retention credit (“CARES Employee Retention Credit”), which is a refundable tax credit against certain employment taxes that the Company qualified for beginning on April 1, 2020. In December 2020, the CARES Employee Retention Credit program was extended and enhanced through June 30, 2021. Further, in March 2021, the ARP further extended the availability of the CARES Employee Retention Credit through December 31, 2021. The ARP increased the credit from 50% to 70% of qualified wages, increased the maximum wages per employee from $10,000 for the entire period to $10,000 per quarter, and expanded the gross receipts test for eligible employers from a 50% to an 80% decline in gross receipts as compared to the same calendar quarter in 2019. If the gross receipts test is met in any quarter, wages earned in the following quarter automatically qualify for the credit and as a result of the increase in revenues during the second and third quarters of 2021, the Company did not qualify for any additional CARES Employee Retention Credits. During the nine months ended September 30, 2021 and the three and nine months ended September 30, 2020, the Company recognized $17 million, $6 million and $11 million, respectively, related to the CARES Employee Retention Credit within CARES Act credits in the Company’s condensed consolidated statements of operations and within other current assets on the Company’s condensed consolidated balance sheets. Income Taxes The Company's effective tax rate for the nine months ended September 30, 2021 was a benefit of 15.5%, compared to a benefit of 45.3% for the nine months ended September 30, 2020. The effective tax rate for the nine months ended September 30, 2021 is lower than the statutory rate primarily due to non-deductible interest from the mark to market adjustments from the warrants issued to the Treasury as part of the Company’s participation in the PSP, PSP2, PSP3, and the Treasury Loan, partially offset by excess tax benefits associated with the Company’s stock-based compensation arrangements. The effective tax rate for the nine months ended September 30, 2020 was favorably impacted the CARES Act benefit that allowed the 2020 net operating loss to be carried back to tax years in which a federal 35% tax rate applied, resulting in a 14% permanent rate benefit. In addition, the prior year rate was also favorably impacted by the inclusion of the tax deduction for the payments made to FAPAInvest, LLC, as described further in Note 9. The resulting effective tax rates for the three months ended September 30, 2021 and 2020 reflect the updates made to the annual estimated effective tax rates for 2021 and 2020, respectively, and the impact from the discrete items.

Revenue Recognition

Revenue Recognition	9 Months Ended
	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Revenue Recognition	Revenue Recognition As of December 31, 2020, the Company’s air traffic liability balance was $135 million. During the nine months ended September 30, 2021, 84% of the air traffic liability as of December 31, 2020 has been recognized as passenger revenue. As of September 30, 2021, the Company’s current air traffic liability is $252 million, of which $72 million is related to customer rights to book future travel, which generally expire 12 months after issuance if not redeemed by the passenger. The amounts expected not to be redeemed are recognized over the historical pattern of rights exercised by customers. During the three and nine months ended September 30, 2021 and 2020, the Company recognized $14 million, $31 million, $22 million and $113 million of revenue, respectively, in passenger revenue within the condensed consolidated statements of operations, primarily related to expected and actual expiration of customer rights to book future travel. Frequent Flyer Program The Company’s Frontier Miles frequent flyer program provides frequent flyer travel awards to program members based on accumulated mileage credits. Mileage credits are generally accumulated as a result of travel, purchases using the co-branded credit card and purchases from other participating partners. The Company defers revenue for mileage credits earned by passengers under its Frontier Miles program based on the equivalent ticket value (“ETV”) a passenger receives by redeeming mileage credits for a ticket rather than paying cash. Mileage credits are also sold to participating companies, including credit card companies and other third parties. Sales to credit card companies include multiple promised goods and services, which the Company evaluates to determine whether they represent performance obligations. The Company determined these arrangements have three separate performance obligations: (i) mileage credits to be awarded, (ii) licensing of brand and access to member lists and (iii) advertising and marketing efforts. Total arrangement consideration is allocated to each performance obligation on the basis of the deliverables relative standalone selling price. For mileage credits, the Company considers a number of entity-specific factors when developing the best estimate of the standalone selling price, including the number of mileage credits needed to redeem an award, average fare of comparable segments, breakage and restrictions. For licensing of brand and access to member lists, the Company considers both market-specific factors and entity-specific factors, including general profit margins realized in the marketplace/industry, brand power, market royalty rates and size of customer base. For the advertising and marketing performance obligation, the Company considers market-specific factors and entity-specific factors, including the Company’s internal costs of providing services, volume of marketing efforts and overall advertising plan. Consideration allocated based on the relative standalone selling price to both the brand licensing and access to member lists and advertising and marketing elements is recognized as other revenue in the Company’s condensed consolidated statements of operations over time as mileage credits are delivered. The consideration allocated to the transportation portion of these mileage credit sales is deferred and recognized as a component of passenger revenue in the Company’s condensed consolidated statements of operations at the time of travel for mileage credits redeemed. Mileage credits the Company estimates are not likely to be redeemed are subject to breakage and are recognized as a portion of passenger revenue in proportion to the pattern of rights exercised by customers. Management uses statistical models to estimate breakage based on historical redemption patterns. A change in assumptions as to the period over which mileage credits are expected to be redeemed, the actual redemption activity for mileage credits or the estimated fair value of mileage credits expected to be redeemed could have an impact on revenues in the year in which the change occurs and in future years. Redemptions are allocated between sold and flown mileage credits based on historical patterns. Operating revenues are comprised of passenger revenues, which includes fare and non-fare passenger revenues, and other revenues. Disaggregated operating revenues are as follows (in millions): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Passenger revenues: Fare $ 254 $ 103 $ 568 $ 446 Non-fare passenger revenues: Baggage 131 48 321 174 Service fees 164 61 368 232 Seat selection 47 16 118 65 Other 14 9 33 33 Total non-fare passenger revenue 356 134 840 504 Total passenger revenues 610 237 1,408 950 Other revenues 20 8 43 33 Total operating revenues $ 630 $ 245 $ 1,451 $ 983 The Company is managed as a single business unit that provides air transportation for passengers. Operating revenues by principal geographic region, as defined by the U.S. Department of Transportation (the “DOT”), are as follows (in millions): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Domestic $ 595 $ 243 $ 1,376 $ 937 Latin America 35 2 75 46 Total operating revenues $ 630 $ 245 $ 1,451 $ 983 During the three and nine months ended September 30, 2021 and 2020, no revenue from any one foreign country represented greater than 5% of the Company’s total passenger revenue. The Company attributes operating revenues by geographic region based upon the origin and destination of each passenger flight segment. The

Other Current Assets

Other Current Assets	9 Months Ended
	Sep. 30, 2021
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Current Assets	Other Current Assets Other current assets consist of the following (in millions): September 30, 2021 December 31, 2020 Prepaid expenses $ 14 $ 24 Income tax receivable 161 161 Passenger and other taxes receivable 10 26 Other 27 15 Total other current assets $ 212 $ 226

Financial Derivative Instrument

Financial Derivative Instruments and Risk Management	9 Months Ended
	Sep. 30, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial Derivative Instruments and Risk Management	Financial Derivative Instruments and Risk Management The Company is exposed to variability in jet fuel prices. Aircraft fuel generally represents the Company’s largest operating expense. Increases in jet fuel prices may adversely impact its financial performance, operating cash flow and financial position. As part of its risk management program, the Company enters into derivative contracts in order to limit exposure to the fluctuations in jet fuel price s. The types of instruments the Company utilized in its 2020 hedging program were call options and collar structures, which include both a purchased call option and sold put option. A lthough the use of collar structures can reduce the overall cost of hedging, these instruments carry more risk than purchased call options alone in that these instruments may result in a net liability for the Company upon settlement. Additionally, the Company is exposed to interest rate risk through aircraft lease contracts for the time period between agreement of terms and commencement of the lease, where portions of the rental payments are adjusted and become fixed based on the seven The Company formally designates and accounts for derivative instruments that meet established accounting criteria under ASC 815, Derivatives and Hedging , as cash flow hedges. For derivative instruments that are designated and qualify as cash flow hedges, the gain or loss on the derivative instruments is recorded in accumulated other comprehensive income/loss (“AOCI/L”), a component of stockholders’ equity on the condensed consolidated balance sheets. The Company recognizes the associated gains or losses deferred in AOCI/L as well as the amounts that are paid or received in connection with the purchase or sale of fuel-related financial derivative instruments (i.e., premium costs of option contracts) as a component of aircraft fuel expense in the period that the jet fuel subject to hedging is consumed for its fuel derivative instruments. For interest rate derivatives, the Company recognizes the associated gains or losses deferred in AOCI/L as well as amounts that are paid or received in connection with the purchase or sale of interest rate derivative instruments (i.e., premium costs of swaption contracts) as a component of aircraft rent expense over the period of the related aircraft lease. The Company does not enter into derivative instruments for speculative purposes. In March 2020, the Company determined that it was no longer probable that estimated future fuel consumption for gallons subjected to fuel hedges would occur, primarily related to second quarter 2020 settled trades as the Company reduced scheduled flights as a result of the decline in customer demand from the COVID-19 pandemic, and, therefore, the Company was required to de-designate certain fuel hedges associated with estimated future consumption declines. The impacts of the de-designation in the Company’s results of operations are reflected in the tables below. As of September 30, 2021, the Company had no fuel derivative contracts or interest rate hedges outstanding. The Company is exposed to credit losses in the event of nonperformance by counterparties to its derivative instruments but does not expect any of its counterparties will fail to meet their obligations. The amount of such credit exposure is generally the fair value of the Company’s outstanding contracts in a receivable position. To manage credit risks, the Company selects counterparties based on credit assessments, limits its overall exposure to any single counterparty and monitors the market position with each counterparty. Based on the fair value of the Company’s fuel derivative instruments, its counterparties may require it to post collateral when the price of the underlying commodity decreases, and the Company may require its counterparties to provide collateral when the price of the underlying commodity increases. The amount of collateral posted, if any, is periodically adjusted based on the fair value of the hedge contracts. The Company’s policy is to offset the liabilities represented by these contracts with any cash collateral paid to the counterparties. The assets and liabilities associated with the Company’s fuel and interest rate derivative instruments are presented on a gross basis and include upfront premiums paid. These assets and liabilities are recorded as a component of other current assets and other current liabilities, respectively, on the Company’s condensed consolidated balance sheets and there were none as of September 30, 2021 and these assets and liabilities were less than $1 million as of December 31, 2020. The following table summarizes the effect of fuel and interest rate derivative instruments reflected in aircraft fuel and rent expense, respectively, within the condensed consolidated statements of operations (in millions): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Derivatives designated as cash flow hedges Losses on fuel derivative contracts $ — $ (11) $ — $ (24) Amortization of swaption cash flow hedges, net of tax $ — $ — $ (1) $ — Derivatives not designated as cash flow hedges Losses on fuel derivative contracts $ — $ (1) $ — $ (56) The following table presents the net of tax impact of the overall effectiveness of derivative instruments designated as cash flow hedging instruments within the condensed consolidated statements of comprehensive income (loss) (in millions): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Derivatives designated as cash flow hedges Fuel derivative contract gains (losses) – net of tax impact $ — $ 7 $ — $ (18) Fuel derivative losses reclassified to earnings due to de-designation – net of tax impact — — — 11 Interest rate derivative contract losses – net of tax impact — — — (10) Amortization of swaption cash flow hedges, net of tax — — 1 — Total $ — $ 7 $ 1 $ (17) As of September 30, 2021, $10 million is included in AOCI/L related to interest rate hedging instruments that is expected to be reclassified into aircraft rent within the condensed consolidated statements of operations over the aircraft lease term of the hedging instrument.

Other Current Liabilities

Other Current Liabilities	9 Months Ended
	Sep. 30, 2021
Other Liabilities Disclosure [Abstract]
Other Current Liabilities	Other Current Liabilities Other current liabilities consist of the following (in millions): September 30, 2021 December 31, 2020 Salaries, wages and benefits $ 84 $ 97 Current portion of phantom equity units (Note 9) 26 — Station obligations 57 33 Leased aircraft return costs 24 20 Aircraft maintenance 28 22 Passenger and other taxes and fees payable 68 41 Fuel liabilities 27 6 Warrant liability — 18 Other current liabilities 35 30 Total other current liabilities $ 349 $ 267

Debt

Debt	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Debt	Debt The Company’s debt obligations are as follows (in millions): September 30, 2021 December 31, 2020 Secured debt: Pre-delivery credit facility (1) $ 126 $ 141 Floating rate building note (2) 18 18 Treasury Loan (3) 150 150 Unsecured debt: Affinity card advance purchase of mileage credits (4) 15 15 PSP Promissory Notes (5) 66 33 Total debt 375 357 Less current maturities of long-term debt, net (85) (101) Less long-term debt acquisition costs and other discounts (10) (9) Long-term debt, net $ 280 $ 247 __________________ (1) The Company, through an affiliate, entered into the pre-delivery payment (“PDP”) facility with Citibank, N.A. in December 2014 (“PDP Financing Facility”). The PDP Financing Facility is collateralized by the Company’s purchase agreement for Airbus A320neo and A321neo aircraft through 2023 (see Note 10). On December 22, 2020, the PDP Financing Facility was amended and restated to reduce the commitment of Citibank, N.A., as initial lender, to $150 million, remove the ability to draw further unsecured borrowings and to provide collateral for the borrowings not secured by aircraft outstanding as of that date. During May 2021, the Company amended the facility to increase the total available capacity to $200 million and expanded the number of financial institution participants as lenders. Interest is paid every 90 days based on a three-month LIBOR plus a margin for each individual tranche. The PDP Financing Facility consists of separate loans for each PDP aircraft. Each separate loan matures upon the earlier of (i) delivery of that aircraft to the Company by Airbus, (ii) the date one month following the last day of the scheduled delivery month of such aircraft and (iii) if there is a delay in delivery of aircraft, depending on the cause of the delivery delay, up to six months following the last day of the scheduled delivery month of such aircraft. The PDP Financing Facility will be repaid periodically according to the preceding sentence with the last scheduled delivery of aircraft contemplated in the PDP Financing Facility expected to be in the fourth quarter of 2023. (2) Represents a note with National Bank of Arizona related to the Company’s headquarters building. Under the terms of the agreement, the Company will repay the outstanding principal balance in quarterly payments beginning in January 2022 until the maturity date in December 2023. On the maturity date, one final balloon payment will be made to cover all unpaid principal, accrued unpaid interest and other amounts due. The interest rate of one-month LIBOR plus a margin is payable monthly. (3) On September 28, 2020, the Company entered into the Treasury Loan with the Treasury for a term loan facility of up to $574 million. The Treasury Loan has a five-year term and includes an annual interest rate based on adjusted LIBOR plus 2.5%. The Company could not draw any further funds from its Treasury Loan facility during the three months ended September 30, 2021, as the right to draw any further funds lapsed as of May 2021, and the Company did not draw any further funds from its Treasury Loan facility during the nine months ended September 30, 2021. The loan can be prepaid at par at any time without incurring a penalty. The Treasury Loan is collateralized by the Company’s co-branded credit card arrangement and related assets. As part of any funding under the loan program, the Company is required to comply with the relevant provisions of the CARES Act, which will apply until one year after the loan is repaid in full. In conjunction with the Treasury Loan, the Company issued to the Treasury warrants to acquire the common stock of FGHI, which have a five-year term and are settled in cash or shares, at the election of the Company, upon notice from the Treasury. The initial fair value of these warrants upon issuance is treated as a loan discount, which reduces the carrying value of the loan, and is amortized utilizing the effective interest method as interest expense in the Company’s condensed consolidated statements of operations over the term of the loan. (4) The Company entered into an agreement with Barclays in 2003 to provide for joint marketing, grant certain benefits to co-branded credit card holders (“Cardholders”), and allow Barclays to market using the Company’s customer database. Cardholders earn mileage credits under the Frontier Miles program and the Company sells mileage credits at agreed-upon rates to Barclays and earns fees from Barclays for the acquisition, retention and use of the co-branded credit card by consumers. In addition, Barclays will pre-purchase miles if the Company meets certain conditions precedent. On September 15, 2020 the Company entered into a new agreement with Barclays to amend and extend the agreement to 2029. The pre-purchased miles facility amount is to be reset on January 15 of each calendar year through and including January 15, 2028 based on the aggregate amount of fees payable by Barclays to the Company on a calendar year basis, up to an aggregate maximum facility amount of $200 million. The facility amount cannot be extended above $15 million until full extinguishment of the Treasury Loan. The Company pays interest on a monthly basis, which is based on a one-month LIBOR plus a margin. Beginning March 31, 2028, the facility will be repaid in 12 equal monthly installments. (5) On April 30, 2020, the Company executed the PSP Promissory Note with the Treasury as part of the original payroll support program from which the Company received a $33 million unsecured 10-year, low-interest loan. Subsequently, the Company entered into a second PSP agreement with the Treasury in January 2021 and a third PSP agreement with the Treasury in April 2021, from which the Company received an additional $18 million and $15 million, respectively, of proceeds with the same terms as the original PSP Promissory Note. The PSP Promissory Notes include an annual interest rate of 1.00% for the first five years and the Secured Overnight Financing Rate ("SOFR") plus 2.00% in the final five years. The loans can be prepaid at par any time without incurring a penalty. In conjunction with the PSP Promissory Notes, the Company issued to the Treasury warrants to acquire the common stock of FGHI, which have a five-year term and are settled in cash or shares, at the election of the Company, upon notice from the Treasury. The initial fair value of these warrants upon issuance is treated as a loan discount, which reduces the carrying value of the loan, and is amortized utilizing the effective interest method as interest expense in the Company’s condensed consolidated statements of operations over the term of the loan. Cash payments for interest related to debt was $7 million and $6 million for the nine months ended September 30, 2021 and 2020, respectively. The Company has issued standby letters of credit and surety bonds to various airport authorities and vendors that are collateralized by restricted cash and as of September 30, 2021 and December 31, 2020, the Company did not have any outstanding letters of credit that were drawn upon. As of September 30, 2021, future maturities of debt are payable as follows (in millions): September 30, 2021 Remainder of 2021 $ 5 2022 106 2023 33 2024 — 2025 150 Thereafter 81 Total debt principal payments $ 375

Operating Leases

Operating Leases	9 Months Ended
	Sep. 30, 2021
Leases [Abstract]
Operating Leases	Operating Leases The Company leases property and equipment under operating leases. For leases with initial terms greater than 12 months, the related asset and obligation is recorded at the present value of lease payments over the term. Some leases include rental escalation clauses, renewal options, termination options, and/or other items that cause variability that are factored into the determination of lease payments when appropriate. The Company does not separate lease and non-lease components of contracts, except for certain flight training equipment, for which consideration is allocated between lease and non-lease components. Aircraft As of September 30, 2021, the Company leased 112 aircraft, all of which are under operating leases with remaining terms ranging from three months to 12 years. In addition, as of September 30, 2021, the Company leased 17 spare engines, which are all under operating leases with the remaining terms for engines included within right-of-use asset and lease liability ranging from four months to 11 years. During the three and nine months ended September 30, 2021 and 2020, the Company executed sale-leaseback transactions with third-party lessors for five, thirteen, four and seven new Airbus A320 family aircraft, respectively. Additionally, the Company did not complete a sale-leaseback transaction for any engines during the three months ended September 30, 2021, and completed a sale-leaseback transaction for one engine during each of the nine months ended September 30, 2021 and the three and nine months ended September 30, 2020. All of the leases from the sale-leaseback transactions are accounted for as operating leases. The Company recognized net sale-leaseback gains from those sale-leaseback transactions of $19 million, $55 million, $18 million and $37 million during the three and nine months ended September 30, 2021 and 2020, respectively, which are included as a component of other operating expenses within the condensed consolidated statements of operations. During the nine months ended September 30, 2021 and 2020, the Company acquired, through new operating leases, aircraft and engines totaling $480 million and $218 million, respectively, which are included in operating lease right-of-use assets on the condensed consolidated balance sheets. In March 2020, the Company entered into two amendments with one lessor that were treated as one combined contract. One amendment extended the remaining lease terms on two aircraft from three In May 2021, the Company entered into an early termination and buyout agreement with one of its lessors for six aircraft that were previously owned by the Company. Of the four A319 aircraft originally slated to be returned in December 2021, two were returned during the second quarter of 2021 and two were returned during the third quarter of 2021, while the two A320 aircraft are to be returned at their originally agreed upon return dates in December 2021. The early returns of these aircraft retired the remaining A319 aircraft in the Company’s fleet. As a result of this early termination and buyout arrangement, the Company recorded a $1 million and $10 million charge included as a component of rent expense within the condensed consolidated statements of operations for the three and nine months ended September 30, 2021, respectively, related to the accelerated rent and lease return obligations of the A319 aircraft returned early. Aircraft Rent Expense and Maintenance Obligations During the three and nine months ended September 30, 2021 and 2020, aircraft rent expense was $128 million, $399 million, $115 million and $266 million, respectively. Aircraft rent expense includes supplemental rent, which is made up of maintenance reserves paid or to be paid that are not probable of being reimbursed and probable lease return condition obligations. Supplemental rent expense for maintenance-related reserves that were deemed non-recoverable was less than $1 million for each of the three and nine months ended September 30, 2021, and less than $1 million and $1 million for the three and nine months ended September 30, 2020, respectively. The portion of supplemental rent expense related to probable lease return condition obligations was $16 million, $41 million, $7 million and $17 million for three and nine months ended September 30, 2021 and 2020, respectively. Additionally, certain of the Company’s aircraft and spare engine lease agreements require the Company to pay maintenance reserves to aircraft lessors to be held as collateral in advance of the Company’s required performance of major maintenance activities. As of September 30, 2021 and December 31, 2020, the Company had aircraft maintenance deposits that are expected to be recoverable of $103 million and $82 million, respectively, on its condensed consolidated balance sheets of which $11 million and less than $1 million, respectively, are included in accounts receivable, net as the eligible maintenance has been performed. The remaining $92 million and $82 million are included within aircraft maintenance deposits on the condensed consolidated balance sheets as of September 30, 2021 and December 31, 2020, respectively. A majority of these maintenance reserve payments are calculated based on a utilization measure, such as flight hours or cycles. Maintenance reserves collateralize the lessor for maintenance time run off the aircraft until the completion of the maintenance of the aircraft. As of September 30, 2021, fixed maintenance reserve payments for aircraft and spare engines, including estimated amounts for contractual price escalations, were expected to be approximately $1 million for the remainder of 2021 and $3 million per year for the years 2022 through 2025 and $12 million thereafter before consideration of reimbursements. Airport Facilities The Company’s facility leases are primarily for space at approximately 120 airports that are served and are primarily located in the United States. These leases are classified as operating leases and reflect the use of airport terminals, ticket counters, office space, and maintenance facilities. Generally, this space is leased from government agencies that control the use of the airport. The majority of these leases are short-term in nature and renew on an evergreen basis. For these leases, the contractual term is used as the lease term. As of September 30, 2021, the remaining lease terms vary from one month to twelve years. At the majority of the U.S. airports, the lease rates depend on airport operating costs or use of the facilities and are reset at least annually. Because of the variable nature of the rates, these leases are not recorded on the condensed consolidated balance sheets as a right-of-use assets and lease liabilities. Other Ground Property and Equipment The Company leases certain other assets such as flight training equipment, building space, and various other equipment. Certain of the Company’s leases for other assets are deemed to contain fixed rental payments and, as such, are classified as operating leases and are recorded on the condensed consolidated balance sheets as a right-of-use asset and liability. The remaining lease terms range from one month to seven years as of September 30, 2021. Lessor Concessions In response to the COVID-19 pandemic, beginning in 2020, the Company was granted payment deferrals on leases included in the Company’s right-of-use assets for certain aircraft and engines from lessors along with airport facilities and other vendors that are not included in the Company’s right-of-use assets. As these deferred payments are made, the Company will recognize the deferred payments in aircraft rent or station operations, as applicable, in the condensed consolidated statements of operations. These deferrals changed operating cash flows and unfavorably impacted the Company’s results of operations by $2 million and $22 million, net, for the three and nine months ended September 30, 2021, respectively, which included a $2 million and $31 million unfavorable impact to aircraft rent within the condensed consolidated statements of operations for the same periods, respectively. There was no impact to station operations for the three months ended September 30, 2021, and a $9 million favorable impact to station operations within the condensed consolidated statements of operations resulting from additional deferrals granted for the nine months ended September 30, 2021, which will be recognized throughout the rest of 2021 and future years as such amounts are paid. The impact of the deferrals on the comparable prior year periods was an unfavorable $8 million and a favorable $64 million to operating cash flows for the three and nine months ended September 30, 2020, respectively, which included a $7 million unfavorable and $50 million favorable impact to aircraft rent and a $1 million unfavorable and $14 million favorable impact to station operations, for the three and nine months ended September 30, 2020, respectively. Lease Costs The table below presents certain information related to lease costs for operating leases during the three and nine months ended September 30, 2021 and 2020 (in millions): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Operating lease cost (1) $ 116 $ 92 $ 357 $ 235 Variable lease cost (1) 76 66 228 127 Total lease costs $ 192 $ 158 $ 585 $ 362 ______________ (1) Expenses are included within aircraft rent, station operations, maintenance materials and repairs and other operating in the Company’s condensed consolidated statements of operations.

Stock-Based Compensation and St

Stock-Based Compensation and Stockholders’ Equity	9 Months Ended
	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation and Stockholders’ Equity	Stock-Based Compensation and Stockholders’ Equity During the three and nine months ended September 30, 2021 and 2020, the Company recognized $3 million, $8 million , $2 million and $6 million, respectively, in stock-based compensation expense, which is included as a component of salaries, wages and benefits within the condensed consolidated statements of operations. Stock Options and Restricted Awards In April 2014, FGHI approved the 2014 Equity Incentive Plan (the “2014 Plan”). Under the terms of the 2014 Plan, 38 million shares of FGHI common stock are reserved for issuance. Concurrently with the Company’s IPO on April 1, 2021, the Company approved the 2021 Incentive Award Plan (the “2021 Plan”), which reserved 7 million shares of FGHI common stock, as well as the 11 million issued awards from the 2014 Plan that are still outstanding plus any subsequently forfeited awards or awards that lapse unexercised after April 1, 2021, to be available for future issuances of stock-based compensation awards to be granted to members of the Board of Directors and certain employees and consultants. Additionally, shares available for issuance under the 2021 Plan will be subject to an annual increase on the first day of each fiscal year beginning in 2022 and ending in 2031, equal to the lesser of (i) one percent (1%) of the shares of stock outstanding on the last day of the immediately preceding fiscal year and (ii) such smaller number of shares of stock as determined by the Company’s Board of Directors; provided, however, that no more than 30 million shares of stock may be issued upon the exercise of incentive stock options. There were no options granted during the nine months ended September 30, 2021 and 2020. During the nine months ended September 30, 2021, 645,966 vested stock options were exercised with a weighted average stock price of $0.73 per share. The weighted average exercise price of outstanding options as of September 30, 2021 was $1.99 per share. During the nine months ended September 30, 2021, 881,450 restricted stock units were issued with a weighted average grant date fair value of $14.65 per share and an aggregate fair value of $13 million. Additionally, during the nine months ended September 30, 2021, the Company withheld 187,051 restricted stock units with a weighted average grant date fair value of $11.18 pe r share to cover employee taxes upon award vesting. Liability-Classified Awards On December 3, 2013, to give effect to the reorganization of the Company’s corporate structure, an agreement was reached to amend and restate a phantom equity agreement with the Company’s pilots. Under the terms of this agreement, when an amendment to the underlying collective bargaining agreement was approved, the Company’s pilots employed by Frontier in June 2011, (the “Participating Pilots”), through their agent, FAPAInvest, LLC, received phantom equity units. Each unit represented the right to receive common stock or cash in connection with certain events, including a qualifying initial public offering, such stock to be distributed or cash paid to the Participating Pilots in 2020 and 2022 based on a predetermined formula. In accordance with the amended and restated phantom equity agreement, the obligation became fixed as of December 31, 2019 and was no longer subject to valuation adjustments. As of December 31, 2019, the final associated liability was $137 million, of which $111 million was paid in March 2020 and the remaining $26 million is to be paid in the first quarter of 2022 and, as such, is presented within other long-term liabilities and other current liabilities on the Company’s condensed consolidated balance sheets as of December 31, 2020 and September 30, 2021, respectively.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Flight Equipment Commitments As of September 30, 2021, the Company’s firm aircraft and engine orders consisted of the following: A320neo A321neo Total Engines Year Ending Remainder of 2021 — — — 1 2022 9 5 14 5 2023 — 19 19 2 2024 — 19 19 2 2025 17 8 25 3 Thereafter 50 16 66 9 Total 76 67 143 22 During December 2017, the Company entered into an amendment to the previously existing master purchase agreement with Airbus. Pursuant to this amendment and subsequent amendments, the Company has a commitment to purchase an incremental 67 A320neo and 67 A321neo aircraft (“incremental aircraft”) which were originally scheduled to be delivered through 2026, and further extended through 2028. The Company, at its option, has the right to convert 18 A320neo aircraft to A321XLR aircraft. The conversion right is not reflected in the table above as this option has not been exercised. The Company’s agreements with Airbus provide for, among other things, varying purchase incentives, which have been allocated proportionally and are accounted for as an offsetting reduction to the cost of the backlog aircraft and increase to the cost of the incremental aircraft. As a result, cash paid for backlog aircraft will be more than the associated capitalized cost of the aircraft and results in the recognition of a deferred purchase incentive within other assets on the condensed consolidated balance sheets, which will ultimately be offset by the lower cash payments in connection with the purchase of the incremental aircraft. During July 2021, the Company signed a letter of intent with two of its leasing partners to add ten additional A321neo aircraft through direct leases, with deliveries beginning in the second half of 2022 and continuing into the first half of 2023. As the aircraft commitments were not yet contractually binding as of September 30, 2021, they are not reflected in the table above. As of September 30, 2021, purchase commitments for these aircraft and engines, including estimated amounts for contractual price escalations and PDPs, were approximately $15 million for the remainder of 2021, $786 million in 2022, $1,097 million in 2023, $1,146 million in 2024, $1,425 million in 2025 and $3,915 million thereafter. Litigation and Other Contingencies On March 12, 2021, the DOT advised the Company that it was in receipt of information indicating that the Company had failed to comply with certain DOT consumer protection requirements relating to consumer refund and credit practices and requested that the Company provide certain information to the DOT. The original DOT request for information and subsequent correspondence and requests have been focused on the Company’s refund practices on Frontier initiated flight cancellations and/or significant changes in flights as a result of the COVID-19 pandemic. The Company is fully cooperating with the DOT request and the review of this matter is still in process. 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 regularly evaluates the status of such matters to assess whether a loss is probable and reasonably estimable in determining whether an accrual is appropriate. Furthermore, in determining whether disclosure is appropriate, the Company evaluates each matter to assess if there is at least a reasonable possibility that a loss or additional losses may have been incurred and whether an estimate of possible loss or range of loss can be made. 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 condensed consolidated financial position, liquidity, or results of operations and that the Company’s current accruals cover matters where loss is deemed probable and can be reasonably estimated. The ultimate outcome of legal actions is unpredictable and can be subject to significant uncertainties, and it is difficult to determine whether any loss is probable or even possible. Additionally, it is also difficult to estimate the amount of loss and there may be matters for which a loss is probable or reasonably possible but not currently estimable. Thus, actual losses may be in excess of any recorded liability or the range of reasonably possible loss. Employees The Company has seven union-represented employee groups that together represent approximately 88% of all employees at September 30, 2021. The table below sets forth the Company’s employee groups and status of the collective bargaining agreements as of September 30, 2021: Percentage of Workforce Employee Group Representative Amendable Date September 30, 2021 Pilots Air Line Pilots Association (ALPA) January 2024 31% Flight Attendants Association of Flight Attendants (AFA-CWA) May 2024 53% Aircraft Technicians International Brotherhood of Teamsters (IBT) March 2024 2% Aircraft Appearance IBT October 2023 1% Material Specialists IBT March 2022 <1% Dispatchers Transport Workers Union (TWU) December 2021 <1% Maintenance Control IBT October 2023 1% The Company is self-insured for health care claims, subject to a stop-loss policy, for eligible participating employees and qualified dependent medical and dental claims, subject to deductibles and limitations. The Company’s liabilities for claims incurred but not reported are determined based on an estimate of the ultimate aggregate liability for claims incurred. The estimate is calculated from actual claim rates and adjusted periodically as necessary. The Company has accrued $5 million and $4 million for health care claims estimated to be incurred but not yet paid as of September 30, 2021 and December 31, 2020, respectively, which is included as a component of other current liabilities on the condensed consolidated balance sheets. General Indemnifications The Company has various leases with respect to real property as well as various agreements among airlines relating to fuel consortia or fuel farms at airports. Under some of these contracts, the Company is party to joint and several liability regarding environmental damages. Under others, where the Company is a member of an LLC or other entity that contracts directly with the airport operator, liabilities are borne through the fuel consortia structure. The Company’s aircraft, services, equipment lease and sale and financing agreements typically contain provisions requiring us, as the lessee, obligor or recipient of services, to indemnify the other parties to those agreements, including certain of those parties’ related persons, against virtually any liabilities that might arise from the use or operation of the aircraft or such other equipment. The Company believes that its insurance would cover most of its exposure to liabilities and related indemnities associated with the commercial real estate leases and aircraft, services, equipment lease and sale and financing agreements described above. Certain of the Company’s aircraft and other financing transactions include provisions that require payments to preserve an expected economic return to the lenders if that economic return is diminished due to certain changes in law or regulations. In certain of these financing transactions and other agreements, the Company also bears the risk of certain changes in tax laws that would subject payments to non-U.S. entities to withholding taxes.

Net Earnings (Loss) per Share

Net Earnings (Loss) per Share	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Net Earnings (Loss) per Share	Net Earnings (Loss) per Share Basic and diluted earnings (loss) per share are computed pursuant to the two-class method. Under the two-class method, the Company attributes net income to common stock and other participating rights (including those with vested share-based awards). Basic net earnings per share is calculated by taking net income, less earnings allocated to participating rights, divided by the basic weighted average common stock outstanding. Net loss per share is calculated by taking net loss divided by basic weighted average common stock outstanding as participating rights do not share in losses. In accordance with the two-class method, diluted net earnings (loss) per share is calculated using the more dilutive impact of the treasury-stock method or from reducing net income for the earnings allocated to participating rights. The following table sets forth the computation of net earnings (loss) per share on a basic and diluted basis pursuant to the two-class method for the periods indicated (in millions, except for share and per share data): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Basic: Net income (loss) $ 23 $ (51) $ (49) $ (98) Less: net income attributable to participating rights (1) — — — Net income (loss) attributable to common stockholders $ 22 $ (51) $ (49) $ (98) Weighted average common shares outstanding, basic 215,452,632 199,307,796 209,816,184 199,235,900 Net earnings (loss) per share, basic $ 0.10 $ (0.26) $ (0.23) $ (0.49) Diluted: Net income (loss) $ 23 $ (51) $ (49) $ (98) Less: net income attributable to participating rights (1) — — — Net income (loss) attributable to common stockholders $ 22 $ (51) $ (49) $ (98) Weighted average common shares outstanding, basic 215,452,632 199,307,796 209,816,184 199,235,900 Effect of dilutive potential common shares 2,802,291 — — — Weighted average common shares outstanding, diluted 218,254,923 199,307,796 209,816,184 199,235,900 Net earnings (loss) per share, diluted $ 0.10 $ (0.26) $ (0.23) $ (0.49) Due to the net loss for the nine months ended September 30, 2021 and for the three and nine months ended September 30, 2020, diluted weighted average shares outstanding are equal to basic weighted average shares outstanding because the effect of all equity awards is anti-dilutive. Approximately 294,679 shares were excluded from the computation of diluted shares for the three months ended September 30, 2021, as their impact would have been anti-dilutive.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Under 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 its financial assets and liabilities. Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents as of September 30, 2021 and December 31, 2020 were comprised of liquid money market funds, time deposits and cash, and are categorized as Level 1 instruments. The Company maintains cash with various high-quality financial institutions. Within restricted cash, the Company may also maintains certificates of deposit that secure certain letters of credit issued for workers’ compensation claim reserves and certain airport authorities. Cash, cash equivalents and restricted cash are carried at cost, which management believes approximates fair value. Warrants The estimated fair value of the warrants issued in conjunction with the loans from the CARES Act, described in Note 2, was previously determined to be Level 3 measurement as of December 31, 2020. As a result of the Company’s IPO, the Company has the intent and ability to settle the warrants issued to the Treasury in shares and thus, as of April 6, 2021, the Company reclassified the warrant liability to additional paid-in capital on the condensed consolidated balance sheet. Subsequent warrants issued after the IPO date were recorded at fair value as a reduction to the related debt they were issued with and recorded to additional paid-in capital on the condensed consolidated balance sheet. As the warrants issued under the CARES Act will no longer be subject to recurring fair value measurements, they have been excluded from the table below as of September 30, 2021. Debt The estimated fair value of the Company’s debt agreements has been determined to be Level 3 measurement, 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 carrying amounts and estimated fair values of the Company’s debt are as follows (in millions): September 30, 2021 December 31, 2020 Carrying Estimated Fair Value Carrying Value Estimated Fair Value Secured debt: Pre-delivery credit facility $ 126 $ 127 $ 141 $ 139 Floating rate building note 18 18 18 18 Treasury Loan 150 155 150 148 Unsecured debt: Affinity card advance purchase of mileage credits 15 14 15 11 PSP Promissory Note 66 56 33 25 Total debt $ 375 $ 370 $ 357 $ 341 The tables below present disclosures about the fair value of assets and liabilities measured at fair value on a recurring basis in the Company’s financial statements (in millions): Fair Value Measurements as of September 30, 2021 Total Level 1 Level 2 Level 3 Cash and cash equivalents $ 802 $ 802 $ — $ — Fair Value Measurements as of December 31, 2020 Total Level 1 Level 2 Level 3 Cash and cash equivalents $ 378 $ 378 $ — $ — Warrants $ 18 $ — $ — $ 18 The Company had no transfers of assets or liabilities between fair value hierarchy levels for December 31, 2020 and September 30, 2021, other than the warrants discussed above.

Related Parties

Related Parties	9 Months Ended
	Sep. 30, 2021
Related Party Transactions [Abstract]
Related Parties	Related Parties Management Services The Company is assessed a quarterly fee to Indigo Partners, LLC (“Indigo Partners”) for management services, plus expense reimbursements and the annual fees of each member of the Company’s board of directors that is affiliated with Indigo Partners. Indigo Partners manages an investment fund that is the controlling stockholder in FGHI. The expenses related to Indigo Partners’ management fees, expense reimbursements and director compensation were less than $1 million for each of the three months ended September 30, 2021 and 2020, and $1 million for each of the nine months ended September 30, 2021 and 2020. Codeshare Arrangement The Company entered into a codeshare agreement with Controladora Vuela Compañía de Aviación, S.A.B. de C.V. (an airline based in Mexico doing business as Volaris) during 2018, under which sales began in July 2018. Two of the Company’s directors are members of the board of directors of Volaris. Indigo Partners holds approximately 18% of the total outstanding Common Stock shares of Volaris.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of PresentationThe condensed consolidated financial statements have been prepared in accordance with the accounting principles generally accepted in the United States (“GAAP”)
Consolidation, Policy	Basis of Presentation The condensed consolidated financial statements have been prepared in accordance with the accounting principles generally accepted in the United States (“GAAP”) and include the accounts of Frontier Group Holdings, Inc. (“FGHI” or the “Company”) and its wholly-owned direct and indirect subsidiaries, including Frontier Airlines Holdings, Inc. (“FAH”) and Frontier Airlines, Inc. (“Frontier”). All wholly-owned subsidiaries are consolidated, with all intercompany transactions and balances being eliminated.
Use of Estimates	Use of EstimatesThe preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities in the financial statements and accompanying notes. Actual results could differ from those estimates.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In December 2019, the FASB issued ASU 2019-12, Simplifying the Accounting for Income Taxes (“ASU 2019-12”). ASU 2019-12 simplifies the accounting for income taxes by removing certain exceptions to the general principles in Topic 740 and also enhances the existing guidance for consistent application of Topic 740. The new guidance is effective for annual periods beginning after December 15, 2020 and interim reporting periods within those reporting periods. The Company adopted the new standard as of January 1, 2021, which did not have a material impact on the Company’s results of operations or financial position as of the adoption date. In August 2020, the FASB issued ASU 2020-06, Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity (“ASU 2020-06”). ASU 2020-06 simplifies the accounting and measurement of convertible instruments and also adds disclosure requirements. Further, ASU 2020-06 simplifies the settlement assessment performed to determine whether a contract in the Company’s own equity qualifies for equity classification. The Company early adopted the standard effective January 1, 2021 using the modified retrospective approach, which did not have a material impact on the Company’s results of operations or financial position as of the adoption date. Given the Company’s IPO in April 2021, and based in part on the provisions of ASU 2020-06, warrants issued in conjunction with the CARES Act that may be settled in the Company’s own equity if publicly traded, were classified into equity during the second quarter of 2021.
Frequent Flyer Program	Frequent Flyer Program The Company’s Frontier Miles frequent flyer program provides frequent flyer travel awards to program members based on accumulated mileage credits. Mileage credits are generally accumulated as a result of travel, purchases using the co-branded credit card and purchases from other participating partners. The Company defers revenue for mileage credits earned by passengers under its Frontier Miles program based on the equivalent ticket value (“ETV”) a passenger receives by redeeming mileage credits for a ticket rather than paying cash. Mileage credits are also sold to participating companies, including credit card companies and other third parties. Sales to credit card companies include multiple promised goods and services, which the Company evaluates to determine whether they represent performance obligations. The Company determined these arrangements have three separate performance obligations: (i) mileage credits to be awarded, (ii) licensing of brand and access to member lists and (iii) advertising and marketing efforts. Total arrangement consideration is allocated to each performance obligation on the basis of the deliverables relative standalone selling price. For mileage credits, the Company considers a number of entity-specific factors when developing the best estimate of the standalone selling price, including the number of mileage credits needed to redeem an award, average fare of comparable segments, breakage and restrictions. For licensing of brand and access to member lists, the Company considers both market-specific factors and entity-specific factors, including general profit margins realized in the marketplace/industry, brand power, market royalty rates and size of customer base. For the advertising and marketing performance obligation,
Operating Leases	The Company leases property and equipment under operating leases. For leases with initial terms greater than 12 months, the related asset and obligation is recorded at the present value of lease payments over the term. Some leases include rental escalation clauses, renewal options, termination options, and/or other items that cause variability that are factored into the determination of lease payments when appropriate. The Company does not separate lease and non-lease components of contracts, except for certain flight training equipment, for which consideration is allocated between lease and non-lease components.
Fair Value Measurement	Under 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 its financial assets and liabilities. Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents as of September 30, 2021 and December 31, 2020 were comprised of liquid money market funds, time deposits and cash, and are categorized as Level 1 instruments. The Company maintains cash with various high-quality financial institutions. Within restricted cash, the Company may also maintains certificates of deposit that secure certain letters of credit issued for workers’ compensation claim reserves and certain airport authorities. Cash, cash equivalents and restricted cash are carried at cost, which management believes approximates fair value. Warrants The estimated fair value of the warrants issued in conjunction with the loans from the CARES Act, described in Note 2, was previously determined to be Level 3 measurement as of December 31, 2020. As a result of the Company’s IPO, the Company has the intent and ability to settle the warrants issued to the Treasury in shares and thus, as of April 6, 2021, the Company reclassified the warrant liability to additional paid-in capital on the condensed consolidated balance sheet. Subsequent warrants issued after the IPO date were recorded at fair value as a reduction to the related debt they were issued with and recorded to additional paid-in capital on the condensed consolidated balance sheet. As the warrants issued under the CARES Act will no longer be subject to recurring fair value measurements, they have been excluded from the table below as of September 30, 2021. Debt

Revenue Recognition (Tables)

Revenue Recognition (Tables)	9 Months Ended
	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	Disaggregated operating revenues are as follows (in millions): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Passenger revenues: Fare $ 254 $ 103 $ 568 $ 446 Non-fare passenger revenues: Baggage 131 48 321 174 Service fees 164 61 368 232 Seat selection 47 16 118 65 Other 14 9 33 33 Total non-fare passenger revenue 356 134 840 504 Total passenger revenues 610 237 1,408 950 Other revenues 20 8 43 33 Total operating revenues $ 630 $ 245 $ 1,451 $ 983
Revenue by Geographic Region	Operating revenues by principal geographic region, as defined by the U.S. Department of Transportation (the “DOT”), are as follows (in millions): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Domestic $ 595 $ 243 $ 1,376 $ 937 Latin America 35 2 75 46 Total operating revenues $ 630 $ 245 $ 1,451 $ 983

Other Current Assets (Tables)

Other Current Assets (Tables)	9 Months Ended
	Sep. 30, 2021
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of Other Current Assets	Other current assets consist of the following (in millions): September 30, 2021 December 31, 2020 Prepaid expenses $ 14 $ 24 Income tax receivable 161 161 Passenger and other taxes receivable 10 26 Other 27 15 Total other current assets $ 212 $ 226

Financial Derivative Instrume_2

Financial Derivative Instruments and Risk Management (Tables)	9 Months Ended
	Sep. 30, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Effect of Fuel and Interest Rate Derivative Instruments Reflected in Aircraft Fuel and Rent Expense	The following table summarizes the effect of fuel and interest rate derivative instruments reflected in aircraft fuel and rent expense, respectively, within the condensed consolidated statements of operations (in millions): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Derivatives designated as cash flow hedges Losses on fuel derivative contracts $ — $ (11) $ — $ (24) Amortization of swaption cash flow hedges, net of tax $ — $ — $ (1) $ — Derivatives not designated as cash flow hedges Losses on fuel derivative contracts $ — $ (1) $ — $ (56)
Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss)	The following table presents the net of tax impact of the overall effectiveness of derivative instruments designated as cash flow hedging instruments within the condensed consolidated statements of comprehensive income (loss) (in millions): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Derivatives designated as cash flow hedges Fuel derivative contract gains (losses) – net of tax impact $ — $ 7 $ — $ (18) Fuel derivative losses reclassified to earnings due to de-designation – net of tax impact — — — 11 Interest rate derivative contract losses – net of tax impact — — — (10) Amortization of swaption cash flow hedges, net of tax — — 1 — Total $ — $ 7 $ 1 $ (17)

Other Current Liabilities (Tabl

Other Current Liabilities (Tables)	9 Months Ended
	Sep. 30, 2021
Other Liabilities Disclosure [Abstract]
Schedule of Other Current Liabilities	Other current liabilities consist of the following (in millions): September 30, 2021 December 31, 2020 Salaries, wages and benefits $ 84 $ 97 Current portion of phantom equity units (Note 9) 26 — Station obligations 57 33 Leased aircraft return costs 24 20 Aircraft maintenance 28 22 Passenger and other taxes and fees payable 68 41 Fuel liabilities 27 6 Warrant liability — 18 Other current liabilities 35 30 Total other current liabilities $ 349 $ 267

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Schedule of Debt Obligations	The Company’s debt obligations are as follows (in millions): September 30, 2021 December 31, 2020 Secured debt: Pre-delivery credit facility (1) $ 126 $ 141 Floating rate building note (2) 18 18 Treasury Loan (3) 150 150 Unsecured debt: Affinity card advance purchase of mileage credits (4) 15 15 PSP Promissory Notes (5) 66 33 Total debt 375 357 Less current maturities of long-term debt, net (85) (101) Less long-term debt acquisition costs and other discounts (10) (9) Long-term debt, net $ 280 $ 247 __________________ (1) The Company, through an affiliate, entered into the pre-delivery payment (“PDP”) facility with Citibank, N.A. in December 2014 (“PDP Financing Facility”). The PDP Financing Facility is collateralized by the Company’s purchase agreement for Airbus A320neo and A321neo aircraft through 2023 (see Note 10). On December 22, 2020, the PDP Financing Facility was amended and restated to reduce the commitment of Citibank, N.A., as initial lender, to $150 million, remove the ability to draw further unsecured borrowings and to provide collateral for the borrowings not secured by aircraft outstanding as of that date. During May 2021, the Company amended the facility to increase the total available capacity to $200 million and expanded the number of financial institution participants as lenders. Interest is paid every 90 days based on a three-month LIBOR plus a margin for each individual tranche. The PDP Financing Facility consists of separate loans for each PDP aircraft. Each separate loan matures upon the earlier of (i) delivery of that aircraft to the Company by Airbus, (ii) the date one month following the last day of the scheduled delivery month of such aircraft and (iii) if there is a delay in delivery of aircraft, depending on the cause of the delivery delay, up to six months following the last day of the scheduled delivery month of such aircraft. The PDP Financing Facility will be repaid periodically according to the preceding sentence with the last scheduled delivery of aircraft contemplated in the PDP Financing Facility expected to be in the fourth quarter of 2023. (2) Represents a note with National Bank of Arizona related to the Company’s headquarters building. Under the terms of the agreement, the Company will repay the outstanding principal balance in quarterly payments beginning in January 2022 until the maturity date in December 2023. On the maturity date, one final balloon payment will be made to cover all unpaid principal, accrued unpaid interest and other amounts due. The interest rate of one-month LIBOR plus a margin is payable monthly. (3) On September 28, 2020, the Company entered into the Treasury Loan with the Treasury for a term loan facility of up to $574 million. The Treasury Loan has a five-year term and includes an annual interest rate based on adjusted LIBOR plus 2.5%. The Company could not draw any further funds from its Treasury Loan facility during the three months ended September 30, 2021, as the right to draw any further funds lapsed as of May 2021, and the Company did not draw any further funds from its Treasury Loan facility during the nine months ended September 30, 2021. The loan can be prepaid at par at any time without incurring a penalty. The Treasury Loan is collateralized by the Company’s co-branded credit card arrangement and related assets. As part of any funding under the loan program, the Company is required to comply with the relevant provisions of the CARES Act, which will apply until one year after the loan is repaid in full. In conjunction with the Treasury Loan, the Company issued to the Treasury warrants to acquire the common stock of FGHI, which have a five-year term and are settled in cash or shares, at the election of the Company, upon notice from the Treasury. The initial fair value of these warrants upon issuance is treated as a loan discount, which reduces the carrying value of the loan, and is amortized utilizing the effective interest method as interest expense in the Company’s condensed consolidated statements of operations over the term of the loan. (4) The Company entered into an agreement with Barclays in 2003 to provide for joint marketing, grant certain benefits to co-branded credit card holders (“Cardholders”), and allow Barclays to market using the Company’s customer database. Cardholders earn mileage credits under the Frontier Miles program and the Company sells mileage credits at agreed-upon rates to Barclays and earns fees from Barclays for the acquisition, retention and use of the co-branded credit card by consumers. In addition, Barclays will pre-purchase miles if the Company meets certain conditions precedent. On September 15, 2020 the Company entered into a new agreement with Barclays to amend and extend the agreement to 2029. The pre-purchased miles facility amount is to be reset on January 15 of each calendar year through and including January 15, 2028 based on the aggregate amount of fees payable by Barclays to the Company on a calendar year basis, up to an aggregate maximum facility amount of $200 million. The facility amount cannot be extended above $15 million until full extinguishment of the Treasury Loan. The Company pays interest on a monthly basis, which is based on a one-month LIBOR plus a margin. Beginning March 31, 2028, the facility will be repaid in 12 equal monthly installments.
Schedule of Maturities of Long-term Debt	As of September 30, 2021, future maturities of debt are payable as follows (in millions): September 30, 2021 Remainder of 2021 $ 5 2022 106 2023 33 2024 — 2025 150 Thereafter 81 Total debt principal payments $ 375

Operating Leases (Tables)

Operating Leases (Tables)	9 Months Ended
	Sep. 30, 2021
Leases [Abstract]
Schedule of Lease Costs	The table below presents certain information related to lease costs for operating leases during the three and nine months ended September 30, 2021 and 2020 (in millions): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Operating lease cost (1) $ 116 $ 92 $ 357 $ 235 Variable lease cost (1) 76 66 228 127 Total lease costs $ 192 $ 158 $ 585 $ 362 ______________

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Long-term Purchase Commitment	As of September 30, 2021, the Company’s firm aircraft and engine orders consisted of the following: A320neo A321neo Total Engines Year Ending Remainder of 2021 — — — 1 2022 9 5 14 5 2023 — 19 19 2 2024 — 19 19 2 2025 17 8 25 3 Thereafter 50 16 66 9 Total 76 67 143 22
Multiemployer Plan	The table below sets forth the Company’s employee groups and status of the collective bargaining agreements as of September 30, 2021: Percentage of Workforce Employee Group Representative Amendable Date September 30, 2021 Pilots Air Line Pilots Association (ALPA) January 2024 31% Flight Attendants Association of Flight Attendants (AFA-CWA) May 2024 53% Aircraft Technicians International Brotherhood of Teamsters (IBT) March 2024 2% Aircraft Appearance IBT October 2023 1% Material Specialists IBT March 2022 <1% Dispatchers Transport Workers Union (TWU) December 2021 <1% Maintenance Control IBT October 2023 1%

Net Earnings (Loss) per Share (

Net Earnings (Loss) per Share (Tables)	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Schedule Of Earnings Per Share Basic And Diluted	The following table sets forth the computation of net earnings (loss) per share on a basic and diluted basis pursuant to the two-class method for the periods indicated (in millions, except for share and per share data): Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Basic: Net income (loss) $ 23 $ (51) $ (49) $ (98) Less: net income attributable to participating rights (1) — — — Net income (loss) attributable to common stockholders $ 22 $ (51) $ (49) $ (98) Weighted average common shares outstanding, basic 215,452,632 199,307,796 209,816,184 199,235,900 Net earnings (loss) per share, basic $ 0.10 $ (0.26) $ (0.23) $ (0.49) Diluted: Net income (loss) $ 23 $ (51) $ (49) $ (98) Less: net income attributable to participating rights (1) — — — Net income (loss) attributable to common stockholders $ 22 $ (51) $ (49) $ (98) Weighted average common shares outstanding, basic 215,452,632 199,307,796 209,816,184 199,235,900 Effect of dilutive potential common shares 2,802,291 — — — Weighted average common shares outstanding, diluted 218,254,923 199,307,796 209,816,184 199,235,900 Net earnings (loss) per share, diluted $ 0.10 $ (0.26) $ (0.23) $ (0.49)

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Schedule of Carrying Values and Estimated Fair Values of Debt Instruments	The carrying amounts and estimated fair values of the Company’s debt are as follows (in millions): September 30, 2021 December 31, 2020 Carrying Estimated Fair Value Carrying Value Estimated Fair Value Secured debt: Pre-delivery credit facility $ 126 $ 127 $ 141 $ 139 Floating rate building note 18 18 18 18 Treasury Loan 150 155 150 148 Unsecured debt: Affinity card advance purchase of mileage credits 15 14 15 11 PSP Promissory Note 66 56 33 25 Total debt $ 375 $ 370 $ 357 $ 341
Schedule of Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis	The tables below present disclosures about the fair value of assets and liabilities measured at fair value on a recurring basis in the Company’s financial statements (in millions): Fair Value Measurements as of September 30, 2021 Total Level 1 Level 2 Level 3 Cash and cash equivalents $ 802 $ 802 $ — $ — Fair Value Measurements as of December 31, 2020 Total Level 1 Level 2 Level 3 Cash and cash equivalents $ 378 $ 378 $ — $ — Warrants $ 18 $ — $ — $ 18

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Basis of Presentation (Details)	9 Months Ended
	Sep. 30, 2021reportableSegmentairport
Accounting Policies [Abstract]
Number of airports served | airport	120
Number of reportable segments | reportableSegment	1

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Initial Public Offering (Details) - USD ($) $ / shares in Units, $ in Millions	Apr. 06, 2021	Apr. 30, 2021
Class of Stock [Line Items]
Underwriting discounts and commissions		$ 14
Offering costs		5
IPO
Class of Stock [Line Items]
Common stock issued (in dollars per share)	$ 19
Common stock issued and sold (in shares)	15,000,000
Proceeds from initial public offering, net of underwriting discounts and offering expenses		$ 266
Public Stock Offering - Shares From Existing Shareholders
Class of Stock [Line Items]
Common stock issued and sold (in shares)	15,000,000
Over-Allotment Option
Class of Stock [Line Items]
Common stock issued and sold (in shares)	4,500,000

Impact of COVID-19 - COVID-19 R

Impact of COVID-19 - COVID-19 Relief Funding (Details) - USD ($)

Sep. 28, 2020

Sep. 30, 2021

Sep. 30, 2020

Sep. 30, 2021

Sep. 30, 2020

Sep. 30, 2021

Sep. 30, 2020

Sep. 30, 2021

Sep. 30, 2021

Sep. 30, 2020

Apr. 29, 2021

Jan. 15, 2021

Dec. 31, 2020

Apr. 30, 2020

Unusual Risk or Uncertainty [Line Items]

CARES Act credits

$ (72,000,000)

$ (97,000,000)

$ (295,000,000)

$ (188,000,000)

Long-term debt, gross

$ 375,000,000

$ 375,000,000

$ 375,000,000

$ 375,000,000

$ 375,000,000

$ 357,000,000

Warrants outstanding, term

5 years

5 years

5 years

5 years

5 years

5 years

Mark to market adjustment on warrant

1,000,000

$ 22,000,000

1,000,000

Employee retention credit

6,000,000

$ 17,000,000

$ 11,000,000

Effective tax rate

(15.50%)

(45.30%)

The Coronavirus Aid, Relief, and Economic Security Act | PSP1 Promissory Note

Unusual Risk or Uncertainty [Line Items]

Funding received

$ 211,000,000

Proceeds from Payroll Support Program grant

$ 178,000,000

Deferred financing costs

1,000,000

1,000,000

CARES Act credits

$ 92,000,000

The Coronavirus Aid, Relief, and Economic Security Act | Consolidated Appropriations Act of 2021 - PSP 2

Unusual Risk or Uncertainty [Line Items]

Funding received

$ 161,000,000

Proceeds from Payroll Support Program grant

$ 143,000,000

The Coronavirus Aid, Relief, and Economic Security Act | American Rescue Plan Act - PSP 3

Unusual Risk or Uncertainty [Line Items]

Proceeds from Payroll Support Program grant

$ 135,000,000

The American Rescue Plan Act | American Rescue Plan Act - PSP 3

Unusual Risk or Uncertainty [Line Items]

Funding received

$ 150,000,000

Proceeds from Payroll Support Program grant

135,000,000

135,000,000

CARES Act credits

$ 72,000,000

PSP Promissory Note Warrants | PSP1 Promissory Note

Unusual Risk or Uncertainty [Line Items]

Warrants to acquire common stock (in shares)

522,576

Exercise price of warrants (in dollars per share)

$ 6.36

PSP2 Promissory Note Warrants | Consolidated Appropriations Act of 2021 - PSP 2

Unusual Risk or Uncertainty [Line Items]

Warrants to acquire common stock (in shares)

157,313

Exercise price of warrants (in dollars per share)

$ 11.65

PSP3 Promissory Note Warrants | American Rescue Plan Act - PSP 3

Unusual Risk or Uncertainty [Line Items]

Warrants to acquire common stock (in shares)

79,961

Exercise price of warrants (in dollars per share)

$ 18.85

CARES Act Credit Agreement, Warrants

Unusual Risk or Uncertainty [Line Items]

Warrants to acquire common stock (in shares)

2,358,090

Exercise price of warrants (in dollars per share)

$ 6.36

Warrants outstanding, term

5 years

Unsecured Debt | PSP1 Promissory Note

Unusual Risk or Uncertainty [Line Items]

Unsecured low interest loan amount

$ 33,000,000

Term of grant

10 years

Unsecured Debt | Consolidated Appropriations Act of 2021 - PSP 2

Unusual Risk or Uncertainty [Line Items]

Unsecured low interest loan amount

$ 18,000,000

Term of grant

10 years

Unsecured Debt | PSP3 Promissory Note

Unusual Risk or Uncertainty [Line Items]

Unsecured low interest loan amount

15,000,000

Term of grant

10 years

Line of Credit | CARES Credit Agreement

Unusual Risk or Uncertainty [Line Items]

Term of grant

5 years

Term loan amount

$ 574,000,000

Long-term debt, gross

$ 150,000,000

$ 150,000,000

$ 150,000,000

$ 150,000,000

$ 150,000,000

$ 150,000,000

Revenue Recognition - Additiona

Revenue Recognition - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Capitalized Contract Cost [Line Items]
Air traffic liability	$ 252		$ 252		$ 135
Customer rights to book future travel	72		72
Passenger revenue recongnized	$ 14	$ 22	$ 31	$ 113
Passenger
Capitalized Contract Cost [Line Items]
Air traffic liability recognized as passenger revenue			84.00%

Revenue Recognition - Disaggreg

Revenue Recognition - Disaggregated Operating Revenues (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 630	$ 245	$ 1,451	$ 983
Total passenger revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	610	237	1,408	950
Fare
Disaggregation of Revenue [Line Items]
Total operating revenues	254	103	568	446
Total non-fare passenger revenue
Disaggregation of Revenue [Line Items]
Total operating revenues	356	134	840	504
Baggage
Disaggregation of Revenue [Line Items]
Total operating revenues	131	48	321	174
Service fees
Disaggregation of Revenue [Line Items]
Total operating revenues	164	61	368	232
Seat selection
Disaggregation of Revenue [Line Items]
Total operating revenues	47	16	118	65
Other
Disaggregation of Revenue [Line Items]
Total operating revenues	14	9	33	33
Other revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 20	$ 8	$ 43	$ 33

Revenue Recognition - Operating

Revenue Recognition - Operating Revenues by Principal Geographic Region (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 630	$ 245	$ 1,451	$ 983
Domestic
Disaggregation of Revenue [Line Items]
Total operating revenues	595	243	1,376	937
Latin America
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 35	$ 2	$ 75	$ 46

Other Current Assets (Details)

Other Current Assets (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid expenses	$ 14	$ 24
Income tax receivable	161	161
Passenger and other taxes receivable	10	26
Other	27	15
Total other current assets	$ 212	$ 226

Financial Derivative Instrume_3

Financial Derivative Instruments and Risk Management - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Derivative [Line Items]
Derivative, other current assets	$ 0		$ 0		$ 1,000,000
Derivative, other current liabilities	0		0		$ 1,000,000
Interest Rate Swap
Derivative [Line Items]
Cost of swap	0	$ 0	0	$ 4,000,000
Notional amount	0		0
Unrealized losses from cash flow hedges net of adjustment for dedesignation of fuel hedges, net of deferred tax benefit			10,000,000
Fuel Derivative Contracts
Derivative [Line Items]
Notional amount	$ 0		$ 0
Minimum
Derivative [Line Items]
Interest rate risk, time period between agreements			7 years
Maximum
Derivative [Line Items]
Interest rate risk, time period between agreements			9 years

Financial Derivative Instrume_4

Financial Derivative Instruments and Risk Management - Effect of Fuel and Interest Rate Derivative Instruments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Fuel Derivative Contracts
Derivative [Line Items]
Losses on fuel derivative contracts	$ 0	$ (11)	$ 0	$ (24)
Amortization of swaption cash flow hedges, net of tax	0	0	0	(11)
Losses on fuel derivative contracts	0	(1)	0	(56)
Interest Rate Swap
Derivative [Line Items]
Amortization of swaption cash flow hedges, net of tax	$ 0	$ 0	$ (1)	$ 0

Financial Derivative Instrume_5

Financial Derivative Instruments and Risk Management - Net of Tax Impact of the Overall Effectiveness of Derivative Instruments Designated as Cash Flow Hedging Instruments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Derivative [Line Items]
Derivative contract losses, net of tax impact	$ 0	$ 7	$ 1	$ (17)
Fuel Derivative Contracts
Derivative [Line Items]
Fuel derivative contract gains (losses) – net of tax impact	0	7	0	(18)
Cash flow hedge reclassified	0	0	0	11
Interest Rate Swap
Derivative [Line Items]
Fuel derivative contract gains (losses) – net of tax impact	0	0	0	(10)
Cash flow hedge reclassified	$ 0	$ 0	$ 1	$ 0

Other Current Liabilities (Deta

Other Current Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Other Liabilities Disclosure [Abstract]
Salaries, wages and benefits	$ 84	$ 97
Current portion of phantom equity units	26	0
Station obligations	57	33
Leased aircraft return costs	24	20
Aircraft maintenance	28	22
Passenger and other taxes and fees payable	68	41
Fuel liabilities	27	6
Warrant liability	0	18
Other current liabilities	35	30
Total other current liabilities	$ 349	$ 267

Debt - Schedule of Debt Obligat

Debt - Schedule of Debt Obligations (Details) - USD ($)	Sep. 28, 2020	Sep. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	May 31, 2021	Dec. 31, 2020	Dec. 22, 2020	Sep. 15, 2020	Apr. 30, 2020
Debt Instrument [Line Items]
Long-term debt, gross		$ 375,000,000	$ 375,000,000		$ 375,000,000		$ 357,000,000
Less current maturities of long-term debt, net		(85,000,000)	(85,000,000)		(85,000,000)		(101,000,000)
Less long-term debt acquisition costs and other discounts		(10,000,000)	(10,000,000)		(10,000,000)		(9,000,000)
Long-term debt, net		$ 280,000,000	$ 280,000,000		$ 280,000,000		247,000,000
Warrants outstanding, term		5 years	5 years		5 years					5 years
CARES Act Credit Agreement, Warrants
Debt Instrument [Line Items]
Warrants outstanding, term	5 years
Secured Debt | Pre-delivery credit facility
Debt Instrument [Line Items]
Long-term debt, gross		$ 126,000,000	$ 126,000,000		$ 126,000,000		141,000,000
Amount of unsecured borrowings available						$ 200,000,000		$ 150,000,000
Secured Debt | Floating rate building note
Debt Instrument [Line Items]
Long-term debt, gross		18,000,000	18,000,000		18,000,000		18,000,000
Secured Debt | Treasury Loan
Debt Instrument [Line Items]
Long-term debt, gross		150,000,000	150,000,000		150,000,000		150,000,000
Unsecured Debt | Affinity card advance purchase of mileage credits
Debt Instrument [Line Items]
Long-term debt, gross		15,000,000	15,000,000		15,000,000		15,000,000
Amount of unsecured borrowings available									$ 200,000,000
Unsecured Debt | PSP Promissory Note
Debt Instrument [Line Items]
Long-term debt, gross		$ 66,000,000	$ 66,000,000		$ 66,000,000		33,000,000
Interest rate		1.00%	1.00%		1.00%
Interest rate period					5 years
Unsecured Debt | PSP Promissory Note | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Debt instrument, variable interest rate					2.00%
Unsecured Debt | PSP1 Promissory Note
Debt Instrument [Line Items]
Loan term				10 years
Unsecured low interest loan amount				$ 33,000,000
Unsecured Debt | Consolidated Appropriations Act of 2021 - PSP 2
Debt Instrument [Line Items]
Loan term					10 years
Unsecured low interest loan amount					$ 18,000,000
Unsecured Debt | PSP3 Promissory Note
Debt Instrument [Line Items]
Loan term		10 years
Unsecured low interest loan amount			$ 15,000,000
Line of Credit | Treasury Loan
Debt Instrument [Line Items]
Long-term debt, gross		$ 150,000,000	$ 150,000,000		$ 150,000,000		$ 150,000,000
Amount of unsecured borrowings available	$ 574,000,000
Loan term	5 years
Period of compliance	1 year
Line of Credit | Treasury Loan | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Debt instrument, variable interest rate	2.50%

Debt - Additional Information (

Debt - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Debt Disclosure [Abstract]
Interest paid	$ 7	$ 6

Debt - Schedule of Maturity (De

Debt - Schedule of Maturity (Details) $ in Millions	Sep. 30, 2021USD ($)
Debt Disclosure [Abstract]
Remainder of 2021	$ 5
2022	106
2023	33
2024	0
2025	150
Thereafter	81
Total debt principal payments	$ 375

Operating Leases - Aircraft (De

Operating Leases - Aircraft (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021USD ($)aircraftaircraftEngine	Sep. 30, 2020USD ($)aircraftEngineaircraft	Sep. 30, 2021USD ($)aircraftEngineaircraft	Sep. 30, 2020USD ($)aircraftaircraftEngine	Dec. 31, 2021aircraft	Jun. 30, 2021aircraft	May 31, 2021aircraft	Mar. 31, 2020USD ($)amendmentaircraft	Feb. 28, 2020
Lessee, Lease, Description [Line Items]
Gains recognized on sale-leaseback transactions | $			$ 55	$ 37
Number of amendments | amendment								2
Number of aircraft renewed								2
Length of contract								5 years	3 years
Return of previously unrecoverable maintenance expense | $								$ 17
Number of aircraft terminated							6
Aircraft
Lessee, Lease, Description [Line Items]
Number of leases	112		112
Aircraft | Minimum
Lessee, Lease, Description [Line Items]
Remaining lease terms	3 months		3 months
Aircraft | Maximum
Lessee, Lease, Description [Line Items]
Remaining lease terms	12 years		12 years
Aircraft Engine
Lessee, Lease, Description [Line Items]
Number of leases | aircraftEngine	17		17
Aircraft Engine | Aircraft Sale Leaseback
Lessee, Lease, Description [Line Items]
Number of sale-leaseback transactions | aircraftEngine	0	1	1	1
Aircraft Engine | Minimum
Lessee, Lease, Description [Line Items]
Remaining lease terms	4 months		4 months
Aircraft Engine | Maximum
Lessee, Lease, Description [Line Items]
Remaining lease terms	11 years		11 years
Aircraft and Aircraft Engines
Lessee, Lease, Description [Line Items]
Gains recognized on sale-leaseback transactions | $	$ 19	$ 18	$ 55	$ 37
Acquired aircraft and engines through operating leases | $			$ 480	$ 218
A-320 | Forecast
Lessee, Lease, Description [Line Items]
Number of aircraft returned					2
A-320 | Aircraft | Aircraft Sale Leaseback
Lessee, Lease, Description [Line Items]
Number of sale-leaseback transactions	5	4	13	7
A-319
Lessee, Lease, Description [Line Items]
Number of aircraft returned	2		2			2
A-319 | Forecast
Lessee, Lease, Description [Line Items]
Number of aircraft terminated					4
A-319, To Be Returned Early
Lessee, Lease, Description [Line Items]
Charge included as a component of rent expense | $	$ (1)		$ (10)

Operating Leases - Aircraft Ren

Operating Leases - Aircraft Rent Expense and Maintenance Obligations (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Leases [Abstract]
Aircraft rent expense	$ 128	$ 115	$ 399	$ 266
Supplemental rent expense for maintenance-related reserves deemed non-recoverable	1	1	1	1
Supplemental rent expense related to probable lease return condition obligations	16	$ 7	41	$ 17
Aircraft maintenance deposits expected to be recoverable	103		103		$ 82
Aircraft maintenance deposits expected to be recoverable, eligible maintenance performed	11		11		1
Aircraft maintenance deposits	92		92		$ 82
Maintenance reserve payments, due remainder of fiscal year	1		1
Maintenance reserve payments, due in year one	3		3
Maintenance reserve payments, due in year two	3		3
Maintenance reserve payments, due in year three	3		3
Maintenance reserve payments, due in year four	3		3
Maintenance reserve payments, due after year four	$ 12		$ 12

Operating Leases - Airport Faci

Operating Leases - Airport Facilities (Details)	9 Months Ended
	Sep. 30, 2021airport
Lessee, Lease, Description [Line Items]
Number of airports served	120
Minimum | Airport Facility
Lessee, Lease, Description [Line Items]
Remaining lease terms	1 month
Maximum | Airport Facility
Lessee, Lease, Description [Line Items]
Remaining lease terms	12 years

Operating Leases - Other Ground

Operating Leases - Other Ground Property and Equipment (Details) - Other Ground Property And Equipment	Sep. 30, 2021
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease terms	1 month
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease terms	7 years

Operating Leases - Lessor Conce

Operating Leases - Lessor Concessions (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Lessee, Lease, Description [Line Items]
Deferrals related to leases	$ (2)	$ (8)	$ (22)	$ 64
Aircraft Rental
Lessee, Lease, Description [Line Items]
Deferrals related to leases	(2)	(7)	(31)	50
Station Operations
Lessee, Lease, Description [Line Items]
Deferrals related to leases	$ 0	$ (1)	$ 9	$ 14

Operating Leases - Lease Cost (

Operating Leases - Lease Cost (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Operating lease cost	$ 116	$ 92	$ 357	$ 235
Variable lease cost	76	66	228	127
Total lease costs	$ 192	$ 158	$ 585	$ 362

Operating Leases - Additional I

Operating Leases - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Cash paid for amounts included in measurement of lease liabilities	$ 116	$ 93	$ 339	$ 237

Stock-Based Compensation and _2

Stock-Based Compensation and Stockholders’ Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 3	$ 2	$ 8	$ 6
Common stock authorized for issuance (in shares)	750,000,000		750,000,000		456,000,000
Preferred stock authorized for issuance (in shares)	10,000,000		10,000,000		1,000,000
Common stock, stated par (in dollars per share)	$ 0.001		$ 0.001		$ 0.001
Preferred stock, par value (in dollars per share)	$ 0.001		$ 0.001
Nonvoting Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock authorized for issuance (in shares)	150,000,000		150,000,000		76,000,000
Common stock, stated par (in dollars per share)	$ 0.001		$ 0.001

Stock-Based Compensation and _3

Stock-Based Compensation and Stockholders’ Equity - Stock Options and Restricted Awards (Details) - USD ($) $ / shares in Units, $ in Millions	Apr. 01, 2021	Sep. 30, 2021	Sep. 30, 2020	Apr. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)		0	0
Stock option exercise (in shares)		645,966
Weighted average stock price (in dollars per share)		$ 0.73
Weighted average exercise price of outstanding options (in dollars per share)		$ 1.99
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units issued (in shares)		881,450
Weighted average grant date fair value (in dollars per share)		$ 14.65
Aggregate fair value		$ 13
Shares withheld to cover employee taxes on vested restricted stock units (in shares)		187,051
Weighted average grant date fair value (in dollars per share)		$ 11.18
2014 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (in shares)				38,000,000
2021 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (in shares)	7,000,000
Common stock issued (in shares)	11,000,000
Maximum number of shares of stock that may be issued upon the exercise of incentive stock options	1.00%
Maximum number of shares of stock that may be issued upon the exercise of incentive stock options (in shares)	30,000,000

Stock-Based Compensation and _4

Stock-Based Compensation and Stockholders’ Equity - Liability-Classified Awards (Details) - USD ($) $ in Millions	1 Months Ended
	Mar. 31, 2020	Sep. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Current portion of phantom equity units		$ 26	$ 0
Phantom Share Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Associated liability, previous				$ 137
Associated liability	$ 111
Current portion of phantom equity units		$ 26
Noncurrent portion of phantom equity units			$ 26

Commitments and Contingencies -

Commitments and Contingencies - Aircraft and Engine Orders (Details)	1 Months Ended		9 Months Ended
	Jul. 31, 2021aircraft	Dec. 31, 2017aircraft	Sep. 30, 2021aircraftEngineaircraft
Air Transportation Equipment
Long-term Purchase Commitment [Line Items]
Remainder of 2021			0
2022			14
2023			19
2024			19
2025			25
Thereafter			66
Total			143
Aircraft Engine
Long-term Purchase Commitment [Line Items]
Remainder of 2021 | aircraftEngine			1
2022 | aircraftEngine			5
2023 | aircraftEngine			2
2024 | aircraftEngine			2
2025 | aircraftEngine			3
Thereafter | aircraftEngine			9
Total | aircraftEngine			22
A320neo | Air Transportation Equipment
Long-term Purchase Commitment [Line Items]
Remainder of 2021			0
2022			9
2023			0
2024			0
2025			17
Thereafter			50
Total		67	76
A321neo | Air Transportation Equipment
Long-term Purchase Commitment [Line Items]
Remainder of 2021			0
2022			5
2023			19
2024			19
2025			8
Thereafter			16
Total	10	67	67

Commitments and Contingencies_2

Commitments and Contingencies - Additional Information (Details) $ in Millions	1 Months Ended		9 Months Ended
	Jul. 31, 2021aircraftleasingPartner	Dec. 31, 2017aircraft	Sep. 30, 2021USD ($)aircraftaircraftEngineemployee_group	Dec. 31, 2020USD ($)aircraft
Long-term Purchase Commitment [Line Items]
Purchase commitments for aircraft and engines, remainder of 2021			$ 15
Purchase commitments for aircraft and engines, 2022			786
Purchase commitments for aircraft and engines, 2023			1,097
Purchase commitments for aircraft and engines, 2024			1,146
Purchase commitments for aircraft and engines, 2025			1,425
Purchase commitments for aircraft and engines, thereafter			$ 3,915
Number of union-represented employee groups | employee_group			7
Amount of employees represented by unions			88.00%
Accrued liabilities for health care claims			$ 5	$ 4
Aircraft Engine
Long-term Purchase Commitment [Line Items]
Number of aircraft agreed to purchase | aircraftEngine			22
Air Transportation Equipment
Long-term Purchase Commitment [Line Items]
Number of aircraft agreed to purchase | aircraft			143
Air Transportation Equipment | A320neo
Long-term Purchase Commitment [Line Items]
Number of aircraft agreed to purchase | aircraft		67	76
Number of aircraft eligible for conversion | aircraft				18
Air Transportation Equipment | A321neo
Long-term Purchase Commitment [Line Items]
Number of aircraft agreed to purchase | aircraft	10	67	67
Number of leasing partners with signed letter of intent | leasingPartner	2

Commitments and Contingencies_3

Commitments and Contingencies - Collective Bargaining Agreements (Details)	9 Months Ended
	Sep. 30, 2021
Multiemployer Plan [Line Items]
Amount of employees represented by unions	88.00%
Pilots
Multiemployer Plan [Line Items]
Amount of employees represented by unions	31.00%
Flight Attendants
Multiemployer Plan [Line Items]
Amount of employees represented by unions	53.00%
Aircraft Technicians
Multiemployer Plan [Line Items]
Amount of employees represented by unions	2.00%
Aircraft Appearance
Multiemployer Plan [Line Items]
Amount of employees represented by unions	1.00%
Material Specialists
Multiemployer Plan [Line Items]
Amount of employees represented by unions	1.00%
Dispatchers
Multiemployer Plan [Line Items]
Amount of employees represented by unions	1.00%
Maintenance Control
Multiemployer Plan [Line Items]
Amount of employees represented by unions	1.00%

Net Earnings (Loss) per Share_2

Net Earnings (Loss) per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Basic:
Net loss	$ 23,000	$ 19,000	$ (91,000)	$ (51,000)	$ 17,000	$ (64,000)	$ (49,000)	$ (98,000)
Less: net income attributable to participating rights	(1,000)			0			0	0
Net income (loss) attributable to common stockholders	$ 22,000			$ (51,000)			$ (49,000)	$ (98,000)
Weighted average common shares outstanding, basic (in shares)	215,452,632			199,307,796			209,816,184	199,235,900
Net earnings (loss) per share, basic (in dollars per share)	$ 0.10			$ (0.26)			$ (0.23)	$ (0.49)
Diluted:
Less: net income attributable to participating rights	$ (1,000)			$ 0			$ 0	$ 0
Net income (loss) attributable to common stockholders	$ 22,000			$ (51,000)			$ (49,000)	$ (98,000)
Effect of dilutive potential common shares (in shares)	2,802,291			0			0	0
Weighted average common shares outstanding, diluted (in shares)	218,254,923			199,307,796			209,816,184	199,235,900
Net earnings (loss) per share, diluted (in dollars per share)	$ 0.10			$ (0.26)			$ (0.23)	$ (0.49)
Shares excluded from the computation of diluted shares (in shares)	294,679

Fair Value Measurements - Carry

Fair Value Measurements - Carrying Amounts and Estimated Fair Values of the Company’s Debt (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, fair value	$ 375	$ 357
Estimated Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, fair value	370	341
Pre-delivery credit facility | Carrying Value | Secured Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, fair value	126	141
Pre-delivery credit facility | Estimated Fair Value | Secured Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, fair value	127	139
Floating rate building note | Carrying Value | Secured Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, fair value	18	18
Floating rate building note | Estimated Fair Value | Secured Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, fair value	18	18
Treasury Loan | Carrying Value | Secured Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, fair value	150	150
Treasury Loan | Estimated Fair Value | Secured Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, fair value	155	148
Affinity card advance purchase of mileage credits | Carrying Value | Unsecured Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, fair value	15	15
Affinity card advance purchase of mileage credits | Estimated Fair Value | Unsecured Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, fair value	14	11
PSP Promissory Note | Carrying Value | Unsecured Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, fair value	66	33
PSP Promissory Note | Estimated Fair Value | Unsecured Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, fair value	$ 56	$ 25

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value of Assets and Liabilities Measured at Fair Value (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 802,000	$ 378,000
Warrants		18,000
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	802,000	378,000
Warrants		0
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Warrants		0
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 0	0
Warrants		$ 18,000

Related Parties (Details)

Related Parties (Details) $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended
	Aug. 31, 2018	Sep. 30, 2021USD ($)director	Sep. 30, 2020USD ($)	Sep. 30, 2021USD ($)director	Sep. 30, 2020USD ($)
Controladora Vuela Compañía de Aviación, S.A.B. de C.V. | Indigo Partners
Related Party Transaction [Line Items]
Outstanding shares of common stock held		18.00%		18.00%
Indigo Partners | Affiliated Entity
Related Party Transaction [Line Items]
Management fees, expense reimbursements, and director compensation | $		$ 1	$ 1	$ 1	$ 1
Controladora Vuela Compañía de Aviación, S.A.B. de C.V. | Affiliated Entity
Related Party Transaction [Line Items]
Number of company directors | director		2		2
Controladora Vuela Compañía de Aviación, S.A.B. de C.V. | Affiliated Entity | Codeshare Arrangement
Related Party Transaction [Line Items]
Effective period of codeshare agreements	3 years