CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS
NET CASH PROVIDED BY OPERATING ACTIVITIES	$ 548,703	$ 582,468
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of marketable securities	(848,897)	(1,469,091)
Sales of marketable securities	878,070	1,566,471
Proceeds from the sale of aircraft, property and equipment	1,612	25,604
Acquisition of property and equipment:
Aircraft and rotable spare parts	(170,392)	(419,508)
Buildings and ground equipment	(9,398)	(61,021)
Deposits on aircraft	(625)	(31,817)
Aircraft deposits applied towards acquired aircraft	9,220	23,298
Net cash received from sale of ExpressJet subsidiary		53,200
Decrease (increase) in other assets	(121,037)	7,570
NET CASH USED IN INVESTING ACTIVITIES	(261,447)	(305,294)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of long-term debt	201,285	99,914
Principal payments on long-term debt	(117,182)	(291,250)
Net proceeds from issuance of common stock	2,819	6,270
Purchase of treasury and common stock and employee income tax paid on equity awards	(26,165)	(93,935)
Increase in debt issuance and lessor initial direct costs	(3,932)	(1,242)
Payment of cash dividends	(13,059)	(17,406)
NET CASH PROVIDED BY (USED IN) FINANCING ACTIVITIES	43,766	(297,649)
Increase (decrease) in cash and cash equivalents	331,022	(20,475)
Cash and cash equivalents at beginning of period	87,206	328,384
CASH AND CASH EQUIVALENTS AT END OF PERIOD	418,228	307,909
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Acquisition of rotable spare parts	8,531	3,662
Debt assumed on aircraft acquired under operating leases		14,475
Engines contributed to joint venture		22,313
Non-cash assets used to acquire aircraft under operating leases		153,566
Lease liability arising from the recognition of right-of-use asset		456,472
CARES Act warrant issuance	8,248
Cash paid during the period for:
Interest, net of capitalized amounts	95,999	100,100
Income taxes	$ 371	2,415
SUPPLEMENTAL DISCLOSURE OF SALE OF SUBSIDIARY:
Decrease in carrying amount of assets		(101,448)
Decrease in carrying amount of liabilities		68,341
Cash received from buyers		79,632
Gain on sale of subsidiary		$ 46,525