Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current Assets
Cash and cash equivalents	$ 24,491	$ 37,170
Restricted cash	516	1,449
Marketable securities	133,303	138,370
Accounts receivable, net	24,119	7,422
Notes receivable	55,177	0
Spare parts and supplies, net	4,729	5,200
Contract costs	358	518
Prepaid expenses and other	1,640	4,174
Total Current Assets	244,333	194,303
Property and Equipment
Flight property and equipment	263,199	259,720
Ground property and equipment	8,320	8,252
Less accumulated depreciation and amortization	(156,909)	(143,313)
Net Property and Equipment	114,610	124,659
Other Assets
Operating lease right-of-use asset	16,005	18,679
Intangibles	5,300	5,300
Long-term deferred tax asset	616	533
Long-term investments	4,275	4,275
Long-term contract costs	0	96
Long-term notes receivable	0	47,568
Other	1,898	3,988
Total Other Assets	28,094	80,439
Total Assets	387,037	399,401
Current Liabilities
Accounts payable	18,574	20,060
Accrued payroll and employee benefits	13,157	14,885
Current portion of operating lease liability	5,103	5,150
Other accrued expenses	196	172
Contract liabilities	4,961	8,098
Deferred revenue	27,500	35,792
Income taxes payable	3,487	0
Current portion of long-term debt (stated principal amount of $7,000 at June 30, 2022 and $3,500 December 31, 2021)	9,310	5,880
Total Current Liabilities	82,288	90,037
Other Long-Term Liabilities
Long-term debt (stated principal amount of $52,500 at June 30, 2022 and $56,000 at December 31, 2021)	57,050	61,670
Long-term promissory note	4,275	4,275
Deferred tax liability	653	688
Long-term operating lease liability	8,304	10,877
Long-term contract liabilities	0	1,326
Deferred revenue, net of current portion	0	9,046
Other	2,662	2,722
Total Long-Term Liabilities	72,944	90,604
Total Liabilities	155,232	180,641
Commitments and Contingencies (Note 8)
Series C Convertible Redeemable Preferred Stock, $0.01 par value, 4,000,000 shares authorized, issued and outstanding at June 30, 2022 and December 31, 2021	13,200	13,200
Stockholders' Equity
Common Stock, $0.01 par value, 100,000,000 shares authorized, 55,481,140 shares issued at June 30, 2022 and December 31, 2021, 46,016,444 shares outstanding at June 30, 2022 and 53,316,299 shares outstanding at December 31, 2021	555	555
Additional paid-in capital	286,064	287,429
Retained deficit	(54,800)	(79,144)
Treasury stock	(13,214)	(3,280)
Total Stockholders' Equity	218,605	205,560
Total Liabilities and Stockholders' Equity	$ 387,037	$ 399,401