Investments in Other Companies (Details) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended		9 Months Ended		12 Months Ended
	Jan. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Sep. 30, 2024 USD ($) shares	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) item shares	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) shares	Dec. 31, 2022 USD ($) $ / shares shares
Long-term debt		$ 3,006,052	$ 2,693,337		$ 2,693,337		$ 3,006,052
Aircraft maintenance, materials and repairs			181,652	$ 178,465	510,334	$ 483,182
Other income (loss) net					$ (6,600)
Fair Value, Net Derivative Asset (Liability), Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]					Other Nonoperating Income (Expense)
Fair Value, Net Derivative Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]					Other Nonoperating Income (Expense)
Aero Engines, LLC. ("Aero Engines")
Payments to acquire interest in joint venture					$ 26,600
Long-term debt			0		0
Aero Engines, LLC. ("Aero Engines") | Other Assets
Investment balance in other companies			$ 23,200		23,200
Aero Engines, LLC. ("Aero Engines") | Other income (loss), net
Company's portion of income (loss) generated by other companies					$ 1,500
Contour Airlines
Payments to acquire equity method investment	$ 15,100	$ 9,900
Investment ownership (as a percent)		9.90%	25.00%		25.00%		9.90%
Number of Board of Directors Seat Held | item					1
Total Number of Board of Directors Seat | item					5
Percentage of Board of Directors Seat Held			20.00%		20.00%
Aircraft maintenance, materials and repairs					$ 12,200
Aircraft and collectible years					4 years
Contour Airlines | Other Assets
Investment balance in other companies			$ 24,400		$ 24,400
Contour Airlines | Other income (loss), net
Company's portion of income (loss) generated by other companies					$ (600)
Eve Holdings, Inc. ("Eve")
Warrants to purchase shares | shares			1,500,000		1,500,000			1,500,000
Warrants exercise price (in dollars per share) | $ / shares								$ 0.01
Initial investment								$ 10,000
Realized loss					$ 1,400
Realized gain on exercise of put options					3,400
Eve Holdings, Inc. ("Eve") | Level 3
Beginning balance	$ 12,477				12,477
Exercise of put option for aircraft parts credits					(3,996)
Realized gain on exercise of put options					3,446
Unrealized loss					(7,067)
Ending balance		$ 12,477	$ 4,860		$ 4,860		$ 12,477
Eve Holdings, Inc. ("Eve") | Put option
Shares obtained | shares								1,000,000
Shares sold | shares					399,589		600,411
Shares reduced | shares							600,411
Eve Holdings, Inc. ("Eve") | Other Assets
Investment balance in other companies			$ 4,900		$ 4,900
Eve Holdings, Inc. ("Eve") | Other income (loss), net
Unrealized losses					$ (8,600)
Eve Holdings, Inc. ("Eve") | Class A common stock
Number of shares acquired | shares								1,000,000