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.
Although it does not fly to Canada, Allegiant advertises extensively there and flies from about a dozen small airports near the Canada–US border. Many of its customers at airports such as Bellingham, Washington (BLI), Niagara Falls, New York (IAG), Ogdensburg, New York (OGS), Grand Forks, North Dakota (GFK) and Plattsburgh, New York (PBG) are Canadians, who can save money by flying from U.S. airports.
In 2013, Allegiant acquired nine Airbus A320-200 aircraft from Spanish flag carrier Iberia. Seven of the A320s were delivered in 2013 and were used for growth into new markets, including destinations in Mexico and the Rocky Mountains, as well as airfields such as Charlottesville and Shenandoah Valley in Virginia and Trenton, New Jersey. On February 24, 2015, Allegiant announced the purchase of 2 additional A320s from Philippine Airlines which entered into service in 2015. Later in 2015, the airline announced a firm order for an Airbus A320 direct from Airbus, the first time it has purchased new aircraft from the supplier.
The company had charter contracts with Caesars Entertainment to ferry customers to Caesars casino properties through Reno-Tahoe International Airport, Laughlin/Bullhead International Airport and Tunica Municipal Airport. These contracts ended in December 2012 when Caesars Entertainment signed a new contract with Republic Airways to provide the charter service to Caesars properties in Atlantic City, New Jersey, Tunica, Mississippi and Laughlin, Nevada.
A November 2016 analysis by the Tampa Bay Times noted that Allegiant's planes were four times more likely to have in-flight failures than other major US airlines. A 60 Minutes report by CBS News in 2018 continued to investigate the issues first raised by the Tampa Bay Times. Public records cited in the investigation found that the airline had more than 100 serious mechanical incidents between January 1, 2016 and October 31, 2017, including "mid-air engine failures, smoke and fumes in the cabin, rapid descents, flight control malfunctions, hydraulic leaks and aborted takeoffs." Other public records further revealed that Allegiant aircraft, on average, were nearly three and a half times more likely to have mid-air breakdowns than American, United, Delta, JetBlue and Spirit.
In December 2006, jetBlue, as part of their RTP plan, removed a row of seats from their A320s to lighten the aircraft by 904 lb (410 kg) and reduce the cabin crew size from four to three (per FAA regulation requiring one flight attendant per 50 seats), thus offsetting the lost revenue from the removal of seats, and further lightening the aircraft, resulting in less fuel burned.
jetBlue previously had its headquarters at 80–02 Kew Gardens Road, and then in the Forest Hills Tower, both in Forest Hills, Queens, New York City, 6 miles (9.7 km) from the current office in Long Island City. In 2001 the airline had announced that it wanted to take 74,000 square feet (6,900 m2) of space in the Forest Hills Tower, and by December 2002 announced that it planned to increase its leased space.
On October 22, 2008, jetBlue opened its new primary hub at John F. Kennedy International Airport (JFK), Terminal 5, or simply T5. The mostly new terminal, costing approximately $800 million, partially encircles the historic TWA Flight Center, the former Trans World Airlines terminal designed by Eero Saarinen, which remains closed. According to the plan, passengers will eventually be able to check in for flights in the landmark building, then transfer to the new structure via the original passenger departing-arrival tubes from Saarinen's original terminal and its 1969 addition by Roche-Dinkeloo.
The airport director in Worcester, Massachusetts, felt that Allegiant reneged on a commitment to serve the airport for five years given the use of federal grants to assist its startup. However, the airline responded that the market was immediately unprofitable and starting service there was a poor decision; flights were reported to be 80% full. Allegiant's flights average 90% full.
The flight personnel and cabin crew where not friendly at all and continuously knocked my shoulders (which where wider than the sear backs) every time they came by and hit my right leg which I had placed on the outside of the seat in front of me as I had a brace on that leg and did say excuse me or I’m sorry the whole time that they hit my leg or my shoulder. By the way and I didn’t tell them but I have undergone reverse shoulder surgery on both of my shoulders/arms and I really don’t expect to get hit every time they pass me
In the fall of 2001, Allegiant exited bankruptcy and the case was officially closed in early 2002. In March 2002, Allegiant entered into a long-term contract with Harrah's to provide charter services to its casinos in Laughlin and Reno, Nevada. At the same time, the airline acquired its first McDonnell Douglas MD-80 jetliner. From 2002 through 2004, the airline developed its scheduled-service business model. By 2004, Allegiant was flying from 13 small cities to Las Vegas offering bundled air and hotel packages.
On September 9, 2014, Frontier introduced an updated livery, as part of a rebranding that saw the spokesanimals' roles increase. The new livery reintroduced a green "FRONTIER" typeface to the fuselage, featuring the stylized "F" designed by Saul Bass for the original Frontier in 1978. Each aircraft features the name of the animal featured on its tail near the nose of the aircraft for easier identification. Currently about twenty five aircraft in the Frontier fleet feature the new livery.