Debt - Schedule of Debt Obligations (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Sep. 28, 2020	Sep. 15, 2020
Debt Instrument [Line Items]
Long-term debt, gross	$ 474,000,000	$ 431,000,000
Less current maturities of long-term debt	(251,000,000)	(157,000,000)
Less debt acquisition costs and other discounts, net	(4,000,000)	(2,000,000)
Long-term debt, net	$ 219,000,000	272,000,000
Periodic payment, interest, period	90 days
Interest paid	$ 28,000,000	14,000,000	$ 9,000,000
Mark to market adjustment on warrant	$ 0	0	$ 22,000,000
CARES Act Credit Agreement, Warrants
Debt Instrument [Line Items]
Warrants to acquire common stock (in shares)				3,117,940
Exercise price of warrants (in dollars per share)				$ 6.95
Warrants exercised (in shares)	0
Secured Debt | Pre-delivery credit facility
Debt Instrument [Line Items]
Long-term debt, gross	$ 312,000,000	277,000,000
Debt issuance costs, net	2,000,000
Amount of unsecured borrowings available	365,000,000
Secured Debt | Floating rate building note
Debt Instrument [Line Items]
Long-term debt, gross	16,000,000	17,000,000
Unsecured Debt | PSP Promissory Notes
Debt Instrument [Line Items]
Long-term debt, gross	$ 66,000,000	66,000,000
Interest rate	1000000.00%
Interest rate period	5 years
Unsecured Debt | PSP Promissory Notes | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Long-term debt, percentage bearing variable interest, percentage rate	2000000.00%
Unsecured Debt | PSP1 Promissory Note
Debt Instrument [Line Items]
Loan term	10 years
Unsecured Debt | Affinity card advance purchase of miles
Debt Instrument [Line Items]
Long-term debt, gross	$ 80,000,000	$ 71,000,000
Amount of unsecured borrowings available					$ 200,000,000