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 August 2017, Allegiant announced a new base would be established at the Indianapolis International Airport. The base began operations in early 2018. In February 2018, Allegiant also announced a new base would be established at the Destin–Fort Walton Beach Airport. In June 2018, Allegiant added another base at McGhee Tyson Airport in Knoxville, Tennessee. In January 2019, Allegiant announced they would be adding another base at Gerald R. Ford International Airport in Grand Rapids, Michigan.
In January 2010, the airline celebrated its one-millionth passenger to fly out of Phoenix-Mesa Gateway Airport. Allegiant's parent company also announced that it had purchased 18 new MD-80 aircraft from Scandinavian Airlines. In February 2010, Allegiant opened its ninth base at Grand Rapids' Gerald R. Ford International Airport in Michigan. The airline based two McDonnell Douglas MD-80 aircraft in Grand Rapids, but ended their airport's status in 2011. The airline continues to fly out of Grand Rapids in a reduced capacity.
Allegiant Air (G4) is an American low-cost carrier that is headquartered in a suburb of Las Vegas. Founded in 1997, the airline does not use hubs, but has designated more than 10 focus cities. These include McCarran International Airport (LAS), Fort Lauderdale–Hollywood International Airport (FLL), Los Angeles International Airport (LAX) and Orlando Sanford International Airport (SFB). Although Allegiant flies into some major airports, many of its destinations are smaller cities or secondary airports that serve larger cities. In total, the airline serves about 105 domestic destinations in 41 states. The airline's fleet of 81 aircraft are each configured with a single Economy Class cabin.