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 2016, a winter weather event disrupted fleet operations, causing Frontier to delay or cancel up to 70% of their flights during the peak of the crisis, many without any advance notice. On the weekend of December 17, the storm caused major delays at Frontier's Denver hub, and the effects of the storm were felt throughout the fleet. Flights were delayed or canceled at airports across the country, as in some cases, planes were ready to depart, but there were no rested flight crews available to service the flight. The head of Frontier's pilot's union issued a statement criticizing the companies' handling of the event, comparing the airline to a "house of cards". Frontier received over 30,000 refund requests for canceled flights resulting from the event.
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.