Proposed Acquisition of Sun Country Airlines Holdings, Inc.	3 Months Ended
Mar. 31, 2026
Discontinued Operations and Disposal Groups [Abstract]
Proposed Acquisition of Sun Country Airlines Holdings, Inc.	Proposed Acquisition of Sun Country Airlines Holdings, Inc. On January 11, 2026, the Company entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Sun Country, under which the Company will acquire Sun Country (the "Merger"). Pursuant to the Merger Agreement, each existing share of Sun Country common stock will be converted into the right to receive (i) $4.10 in cash, without interest and (ii) 0.1557 shares of the Company's common stock. Completion of the Merger is subject to the satisfaction or waiver of certain closing conditions, including, among other things, (1) approval of the Merger by Sun Country stockholders, (2) approval of the issuance of shares of Allegiant Travel Company Common Stock pursuant to the Merger Agreement by the Company's stockholders, (3) receipt of applicable regulatory approvals, including approvals from the U.S. Federal Aviation Administration and the U.S. Department of Transportation (the "DOT"), and the expiration or early termination of the statutory waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended ("HSR"); (4) the absence of any law or order prohibiting the consummation of the transactions; (5) the effectiveness of the registration statement filed by Allegiant and Sun Country with the SEC pursuant to the Merger Agreement; and (6) the authorization and approval for listing on NASDAQ of the shares of Allegiant Common Stock to be issued to holders of Sun Country Common Stock in the Merger. On March 16, 2026, the Department of Justice granted early termination of the HSR statutory waiting period with respect to the Merger. On April 15, 2026, the DOT approved the joint interim exemption application that will allow both Allegiant and Sun Country to continue operating as separate carriers under common ownership after closing, pending further action by the DOT, satisfying the last remaining regulatory approval-related condition to the closing of the proposed Merger. On April 2, 2026, notice was given that a special meeting of stockholders (the “Special Meeting”) of the Company will be held on May 8, 2026, to consider and vote on a proposal to approve the issuance of Allegiant common stock in connection with the Merger and a proposal to give the Allegiant board authority to adjourn the Allegiant special meeting from time to time, if necessary or appropriate, to solicit additional proxies in the event there are not sufficient votes at the time of the Allegiant Special Meeting to approve the share issuance proposal. The Merger is expected to close as early as May 13, 2026, subject to satisfaction or waiver of the remaining conditions to closing. To date, the Company has incurred $13.7 million in costs related to merger and integration activities, including costs recorded in fourth quarter 2025. Future financial impacts are not yet estimable.

On January 11, 2026, the Company entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Sun Country, under which the Company will acquire Sun Country (the "Merger"). Pursuant to the Merger Agreement, each existing share of Sun Country common stock will be converted into the right to receive (i) $4.10 in cash, without interest and (ii) 0.1557 shares of the Company's common stock.

Completion of the Merger is subject to the satisfaction or waiver of certain closing conditions, including, among other things, (1) approval of the Merger by Sun Country stockholders, (2) approval of the issuance of shares of Allegiant Travel Company Common Stock pursuant to the Merger Agreement by the Company's stockholders, (3) receipt of applicable regulatory approvals, including approvals from the U.S. Federal Aviation Administration and the U.S. Department of Transportation (the "DOT"), and the expiration or early termination of the statutory waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended ("HSR"); (4) the absence of any law or order prohibiting the consummation of the transactions; (5) the effectiveness of the registration statement filed by Allegiant and Sun Country with the SEC pursuant to the Merger Agreement; and (6) the authorization and approval for listing on NASDAQ of the shares of Allegiant Common Stock to be issued to holders of Sun Country Common Stock in the Merger.

On March 16, 2026, the Department of Justice granted early termination of the HSR statutory waiting period with respect to the Merger. On April 15, 2026, the DOT approved the joint interim exemption application that will allow both Allegiant and Sun Country to continue operating as separate carriers under common ownership after closing, pending further action by the DOT, satisfying the last remaining regulatory approval-related condition to the closing of the proposed Merger.

On April 2, 2026, notice was given that a special meeting of stockholders (the “Special Meeting”) of the Company will be held on May 8, 2026, to consider and vote on a proposal to approve the issuance of Allegiant common stock in connection with the Merger and a proposal to give the Allegiant board authority to adjourn the Allegiant special meeting from time to time, if necessary or appropriate, to solicit additional proxies in the event there are not sufficient votes at the time of the Allegiant Special Meeting to approve the share issuance proposal.