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 March 2011, Allegiant took over charter service to Wendover Airport for Peppermill Casinos, Inc. to shuttle customers to Peppermill's three casinos in West Wendover, Nevada; the Montego Bay Resort, the Rainbow Wendover and the Peppermill Wendover. Allegiant based one 150-seat, MD-80 series jet aircraft in Wendover and more than 20 employees, including maintenance, flight crews and stations personnel.
While its financial performance started showing signs of improvement, in February 2007, jetBlue faced a crisis, when a snowstorm hit the Northeast and Midwest, throwing the airline's operations into chaos. Because jetBlue followed the practice of never cancelling flights, it desisted from calling flights off, even when the ice storm hit and the airline was forced to keep several planes on the ground. Because of this, passengers were kept waiting at the airports for their flights to take off. In some cases, passengers who had already boarded their planes were kept waiting on the apron for several hours and were not allowed to disembark. However, after all this, the airline was eventually forced to cancel most of its flights because of prevailing weather conditions. The fiasco reportedly cost JetBlue $30 million.
On November 15, 2017 Frontier Airlines announced a $15 billion order for 134 additional A320neo family aircraft. The order, slightly revised under new owner Indigo, consists of 100 A320neo and 34 A321neo. The order also includes the conversion of the remaining A319neo to A320neo. With this order, Frontier Airlines fleet has industry-leading fuel efficiency. The fleet is also one of the most modern and young, particularly in comparison to other low-cost carriers,[nt 1] at an average age of 5 years as of 2018.
Like Ryanair, the low-cost airline founded by the Ryan family of Ireland, who also have invested in Allegiant, the airline seeks ancillary revenue to supplement ticket revenue. These ancillary fees include those for checking luggage, carrying on luggage (other than a small personal item), buying food and drinks on board, obtaining advance seat assignments, and more. Allegiant CEO Maurice Gallagher said in 2009, "We collect $110 from you at the end of your trip. If I tried to charge you $110 up front, you wouldn't pay it. But if I sell you a $75 ticket and you self-select the rest, you will."
The initial JetExpress partnership with Mesa ended in January 2004, when Horizon Air was selected to operate the routes. Horizon utilized slightly larger CRJ-700 regional jet aircraft on these routes. In August 2006, Frontier and Horizon ended their partnership. While Frontier was generally pleased with Horizon's operation, the carrier decided that it needed to revisit the agreement and find a provider with additional regional jets to grow the operation. The last of the CRJ-700's was returned to the Horizon Air fleet on November 30, 2007.