Allegiant Air is an American discount airline and the 9th largest airline in the U.S. They are headquartered in Las Vegas and fly to about 120 destinations. They aren't included in any major airline alliances, so you'll have to be on the lookout for non-transfer options if you want to book flights with them.

Allegiant Air, primarily known as a standalone ultra-low-cost carrier based in Las Vegas, recently underwent a massive structural shift. On January 11, 2026, Allegiant and Sun Country Airlines announced a definitive merger agreement. Under this deal, Allegiant is acquiring Sun Country to create a premier leisure-focused U.S. airline. While they previously operated as independent competitors with different business models (Allegiant focused on small-city-to-vacation-spot routes and Sun Country on scheduled service and charter/cargo), they are now becoming sister brands within a single corporate entity. This affiliation allows them to leverage Allegiant's massive domestic footprint alongside Sun Country's existing cargo contracts with Amazon and their diverse charter operations. For passengers, this means a more integrated network for leisure travel, particularly for flights connecting the Midwest and the Sun Belt.

Allegiant Air is an independent ultra-low-cost carrier and is not formally affiliated with any major airline alliance or another airline through codeshare agreements. However, it does have interline agreements with a few airlines, allowing limited cooperation on baggage handling and connections (though not full codeshares or frequent flyer partnerships).

Key Points:

1. No Major Airline Affiliation – Allegiant operates independently and is not part of alliances like SkyTeam, Star Alliance, or Oneworld.
2. Interline Partners – Allegiant has limited interline agreements with airlines like American Airlines, Delta Air Lines, and United Airlines, primarily for baggage transfers on separate tickets.
3. Focus on Leisure Travel – Allegiant specializes in point-to-point flights to vacation destinations, often serving smaller airports.

If you’re looking for reciprocal benefits (like mileage earning or elite status recognition), Allegiant does not have partnerships like those seen among major network airlines. Its loyalty program, Allways Rewards, is standalone.

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