Various consumer rights organizations and activists called for the creation of a government mandated “Bill of Rights” to protect air travelers from future experiences similar to the one previously described. On February 20, 2007, jetBlue released an apologetic response to the events that had taken place less than a week before with the creation of their Customer Bill of Rights, which offers financial reciprocation if a customer's flight is delayed or cancelled.
Frontier took delivery of its first Airbus aircraft (an A319) in 2001 and simultaneously launched with it DirecTV in-flight television along with a new company livery. Frontier Airlines was the launch customer of the Airbus A318 in 2003. In mid-April 2005, Frontier officially became an all-Airbus fleet, retiring its last Boeing 737.
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.
Scheduled service began on October 15, 1998, between Las Vegas and the airline's original hub in Fresno, California, at the Fresno Yosemite International Airport, with Douglas DC-9-21 and McDonnell Douglas DC-9-51 jetliners. During the second half of 1999, the airline was operating nonstop flights between Fresno and Las Vegas, Burbank and Lake Tahoe, and Las Vegas and Lake Tahoe as well as flying one-stop direct service between Fresno and Lake Tahoe via Las Vegas. Shortly after WinAir Airlines closed in 1999, Allegiant Air opened a small hub in Long Beach, CA (LGB) and in 2000 was operating nonstop flights to Fresno and Las Vegas in addition to Fresno-Las Vegas nonstop service. Later in 2000, Allegiant continued to expand and was operating the only nonstop jet service between Lake Tahoe Airport from Long Beach in addition to operating new flights into Portland, Oregon and Reno with Portland-Reno and Reno-Fresno nonstops and direct one-stop service between Portland and Fresno via Reno. Citing higher fuel costs as a major factor, Allegiant filed for Chapter 11 bankruptcy protection in 2000.
Dave Siegel took the chief executive officer role in January 2012. Siegel's tenure ran through May 2015, when he left for personal reasons and was succeeded by the company's chairman, Bill Franke, who would manage strategy and finances. In April 2014, Barry L. Biffle was appointed as the company's president, reporting to Siegel; after Siegel's departure, Biffle was charged with managing the company's day-to-day operations.
In March 2010, Allegiant purchased six used Boeing 757-200 jetliners as part of plans to begin flights to Hawaii, with deliveries from early 2010 to the fourth quarter of 2011. It gained the approval for type with the FAA in July 2011, and then worked with the FAA to obtain the appropriate ETOPS rating in order to be able to serve Hawaii. Allegiant no longer operates nonstop service to Honolulu from Las Vegas.