Investments in Other Companies (Details) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended		12 Months Ended
	Jan. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Mar. 31, 2025 USD ($) item shares	Mar. 31, 2024 USD ($)	Dec. 31, 2024 USD ($) shares	Dec. 31, 2023 shares	Dec. 31, 2022 USD ($) $ / shares shares
Long-term debt			$ 2,559,582		$ 2,672,375
Aircraft maintenance, materials, and repairs			209,100	$ 145,415
Other income (loss) net			$ (3,200)	$ (3,500)
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
Investment ownership (as a percent)			75.00%
Long-term debt			$ 0
Aero Engines, LLC. ("Aero Engines") | Other Assets
Investment balance in other companies			24,500
Aero Engines, LLC. ("Aero Engines") | Other income (loss), net
Company's portion of income (loss) generated by other companies			$ 600
Contour Airlines
Investment ownership (as a percent)		9.90%	25.00%			9.90%
Payments to acquire equity method investment	$ 15,100	$ 9,900
Number of Board of Directors seats held | item			1
Total number of Board of Directors seats | item			5
Percentage of Board of Directors seats held			20.00%
Aircraft maintenance, materials, and repairs			$ 11,100
Aircraft and collectible years			4 years
Contour Airlines | Other Assets
Investment balance in other companies			$ 22,300
Contour Airlines | Other income (loss), net
Company's portion of income (loss) generated by other companies			$ 900
Eve Holdings, Inc. ("Eve")
Warrants to purchase shares | shares			1,500,000				1,500,000
Warrants exercise price (in dollars per share) | $ / shares							$ 0.01
Initial investment							$ 10,000
Eve Holdings, Inc. ("Eve") | Level 3
Beginning balance			$ 8,160
Unrealized gain (loss)			3,180
Ending balance			4,980		$ 8,160
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			$ 5,000		$ 8,200
Eve Holdings, Inc. ("Eve") | Class A common stock
Number of shares acquired | shares							1,000,000