Allegiant Air has been closely monitored by the FAA due to many emergency landings and aborted takeoffs. ABC interviewed a former Allegiant mechanic, who said "Dedicated steps were not being performed with maintenance manuals or even with general practices, before an aircraft is released." Many of these incidents had involved Allegiant's aging MD-80 aircraft, which as of November 2018 have been replaced by newer Airbus A320 family aircraft. 46 of the 86 aircraft have made emergency landings, all of which were on MD-80s. The average age of Allegiant's MD-80 fleet was 29 years compared to less than 13 years for its Airbus fleet.
September 21, 2005: Flight 292 en route from Burbank, California, to New York City performed an emergency landing at Los Angeles International Airport (pictured on the right) following a failure of the front landing gear during retraction when it turned 90 degrees. The plane landed after holding for about three hours to burn fuel and therefore lighten the aircraft. The aircraft came to a stop without incident on runway 25L, the second-longest runway at LAX. The only apparent damage to the plane upon landing was the destruction of the front wheels, which were ground down to almost semicircles, and the tires; the front landing strut held. The passengers were unable to see themselves landing despite the DirecTV service in each seat, as they were instructed to brace.
In July 2012, Allegiant announced the future addition of the Airbus A319-100 aircraft to its fleet. The aircraft are used and formerly belonged to easyJet and Cebu Pacific. All of them are high-density A319s, fitted with four overwing exits, allowing 156 seats. Two former easyJet aircraft entered service in 2013, with another in 2014 and an additional six in 2015. In December 2012, Allegiant cancelled the agreement with Cebu Pacific citing an inability to agree on economic provisions. On May 1, 2013, Allegiant purchased another A319 aircraft previously operated by easyJet that would enter service in the third quarter of 2013. On February 23, 2015, Allegiant purchased six more A319s from Cebu Pacific.
On June 22, 2009, Frontier Airlines announced that pending bankruptcy court approval, Republic Airways Holdings, the Indianapolis-based parent company of Republic Airlines, would acquire all assets of Frontier Airlines for the amount of $108 million. Thus, Frontier Airlines would become a wholly owned subsidiary of Republic. However, 5 weeks later on July 30, Dallas-based Southwest Airlines announced that it would be making a competing bid of $113.6 million for Frontier with intentions to also operate Frontier as a wholly owned subsidiary, but that it would gradually fold Frontier resources into current Southwest operating assets.
The TWA Hotel is the TWA Flight Center structure currently being rebuilt as 505-room hotel, preserving the Eero Saarinen headhouse while replacing the structures on either side of the headhouse. Situated in front of JetBlue's JFK terminal, JetBlue has stated that it estimates the ownership of the hotel would be between 5–10% of the final total investment. The hotel will be an effective replacement for the Ramada Plaza JFK Hotel on the north end of the airport grounds in Building 144, which closed in 2009.
On July 1, 2010 Allegiant returned to Long Beach Airport (LGB) in Long Beach, California having previously served LGB with DC-9 jets with nonstop flights to Las Vegas (LAS) and Lake Tahoe (TVL) in 2000. The airline also intended to fly from Bellingham International Airport and Stockton several times a week; however, there is no service at present flown between these two cities although Allegiant continues to serve Stockton with flights to Las Vegas, Phoenix/Mesa and San Diego. In November 2011, Allegiant closed its Long Beach facility and consolidated all Los Angeles area flights at Los Angeles International (LAX).