MERGER WITH MESA AIR GROUP, INC. - Schedule of Purchase Price Consideration (Details) $ / shares in Units, $ in Millions	Nov. 25, 2025 USD ($) $ / shares shares	Mar. 31, 2026 shares	Dec. 31, 2025 shares	Nov. 24, 2025 shares
Business Combination [Line Items]
Common stock, shares outstanding (in shares)		45,604,180	45,713,286
Republic Airways Holdings Inc.
Business Combination [Line Items]
Common stock, shares outstanding (in shares)	46,949,601
Exchange Ratio	38.9933
Price per share at fair value (in dollars per share) | $ / shares	$ 21.00
Implied enterprise value | $	$ 985.9
Equity Merger consideration at fair value | $	117.5
Other consideration at fair value | $	2.7
Total Merger consideration | $	$ 120.2
Republic Airways Holdings Inc. | Legacy Republic
Business Combination [Line Items]
Common stock, shares outstanding (in shares)	1,025,264			1,004,108
Republic equity relinquished	11.90%
Republic Airways Holdings Inc. | Legacy Republic | Restricted Stock Units (RSUs)
Business Combination [Line Items]
Shares issued in period (in shares)	21,156
Republic Airways Holdings Inc. | Legacy Republic | Restricted Stock
Business Combination [Line Items]
Shares issued in period (in shares)	1,264,210
Republic Airways Holdings Inc. | Mesa Air Group, Inc.
Business Combination [Line Items]
Common stock, shares outstanding (in shares)	2,853,542			2,792,531
Resulting shares of Mesa common stock issued for Republic shares outstanding (in shares)	39,978,395
Shares of common stock of Mesa before the application of the Three Party Agreement (in shares)	44,096,147
Mesa common stock issued in accordance with the Three Party Agreement (6.0% of the total Mesa shares of common stock at closing of the Merger) (in shares)	2,853,454
Escrow shares held, percent	6.00%
Republic Airways Holdings Inc. | Mesa Air Group, Inc. | Restricted Stock Units (RSUs)
Business Combination [Line Items]
Shares issued in period (in shares)	61,011