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DEBT - Long-term Debt Schedule (Details) - USD ($)	Mar. 31, 2022	Dec. 31, 2021	Dec. 31, 2019
DEBT
Total Debt	$ 280,970,000	$ 280,931,000
Less: Unamortized debt issuance costs	(3,685,000)	(3,505,000)
Less: Current Maturities of Long-term Debt	(34,741,000)	(29,412,000)
Total Long-term Debt	242,544,000	248,014,000
Notes payable under the Company's 2019-1 EETC agreement \| Notes payable
DEBT
Total Debt	$ 202,984,000	202,984,000
Face amount			$ 248,587,000
Weighted average interest rate	4.76%
Notes payable under the Company's 2019-1 EETC agreement \| Minimum \| Notes payable
DEBT
Interest Rate			4.13%
Notes payable under the Company's 2019-1 EETC agreement \| Maximum \| Notes payable
DEBT
Interest Rate			6.95%
Notes payable under the Company's 2022-1 EETC agreement \| Notes payable
DEBT
Total Debt	$ 77,986,000	0
Face amount	$ 188,277,000
Weighted average interest rate	5.06%
Notes payable under the Company's 2022-1 EETC agreement \| Minimum \| Notes payable
DEBT
Interest Rate	4.84%
Notes payable under the Company's 2022-1 EETC agreement \| Maximum \| Notes payable
DEBT
Interest Rate	5.75%
Delayed Draw Term Loan Facility \| Loans Payable
DEBT
Total Debt	$ 0	77,481,000
Notes payable
DEBT
Total Debt	$ 0	$ 466,000
Notes payable \| Notes payable
DEBT
Interest Rate	5.00%