Founded in 1997 as WestJet Express, the company was renamed as Allegiant Air and started operations under the new name in 1998. From there on, company went on to become one of the most favorite low-cost airlines of America with their unmatched reliability, customer care and best in-class deals. Owned by Allegiant Travel Co. Allegiant Air have their headquarters in Enterprise, Nevada near Las Vegas. Today it has more than 1300 employees and over a billion USD capitalizations.
jetBlue expanded service to the Caribbean, including to St. Maarten and Puerto Plata commencing January 10, 2008. With these additional destinations, jetBlue serves a total of twelve Caribbean/Atlantic destinations including Aruba; Barbados; Bermuda; Cancún; Nassau; Aguadilla; Ponce; San Juan, Puerto Rico; Santiago; and Santo Domingo, Dominican Republic.
In May 2017, Allegiant Air took delivery of its first brand-new A320. Allegiant took delivery of ten new A320s in 2017 and is scheduled to accept two in 2018. All new aircraft will be painted in Allegiant's new livery at the time it is delivered. Older Airbus aircraft will be repainted during their C-checks. The new Airbus aircraft will have fuel-efficient sharklets. The new A320s seat 186 passengers, an increase of the 177 seats that are found in the rest of the Allegiant A320 fleet. To fit the additional nine seats, Allegiant opted for the Airbus Space-Flex V2 Lavatory. 
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.
On October 13, 2009, the airline unveiled a modification to its livery in commemoration of the upcoming 10th anniversary of the airline in February 2010. Besides a new tail design, the revised livery includes larger "billboard" titles extending down over the passenger windows at the front of the aircraft. The logo word 'jetBlue' will no longer be silver and blue but now a dark, navy blue.
At the checkin there was a male and I am assuming he was from Jamaica who was very impatient with us. We had even got our bags to the checkin before he was asking for our boarding passes and I’d cards. He stated that the boarding passes we had (which we printed the day before) would not work and through our boarding passes in the trash and after we presented our I’d cards proceeded to print out new boarding passes and our baggage claim tickets.
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.
A new marketing strategy has been partnerships with professional sports teams and venues. As the official airline of the New York Jets, JetBlue has specially painted the exterior of one of their Airbus A320s (N746JB) in the team's colors. Aircraft N605JB is based on the design of the Boston Red Sox road uniform and sports a grey fuselage with navy lettering. This aircraft was unveiled in February 2012, just in time for the opening of the Red Sox new spring training facility in Fort Myers, Florida named JetBlue Park at Fenway South. Additionally, JetBlue and MasterCard have pledged to refund select flight purchases made online at JetBlue.com using a MasterCard. JetBlue has also partnered with various other sports teams and sporting venues in cities they serve.
On October 25, 2007, the airline opened a fourth focus city and operations base at Phoenix-Mesa Gateway Airport in Mesa, Arizona, connecting 13 cities already served by Allegiant and one new city to the Phoenix metropolitan area. The airport announced a 10,000-square-foot (930 m2) expansion in August 2008, which increased the number of gates from two to four and allowed Allegiant to triple the number of flights from Phoenix. The expansion was funded by a loan from Allegiant which will be repaid by passenger fees.
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.