The eighth largest commercial airlines in United States with its headquarters in Denver, Colorado- Frontier Airlines is an ultra low cost carrier airlines which operates flights to over 80 destinations in United States itself along with six international destinations. With more than 3000 employees, this airline is operating brand of Indigo partners, LLC, and has a hub at Denver International Airport. Frontier began linking passengers with Mexican low-cost carrier in August 2018, Volaris under code share agreement

Frontier Airlines was built-in on February 8, 1994, by a group of executives of the original foundation of Frontier Airlines with scheduled flights which began five months later in July 1994 using Boeing 737-200 jetliners on routes between Denver plus four other destinations in North Dakota: Bismarck, Minot, Fargo and Grand Forks. Frontier had expanded its route network by January 1995 from Denver and was serving Albuquerque, New Mexico; Billings, Montana; Bismarck, N.D.; Bozeman, Montana; El Paso, Texas; Fargo, N.D.; Great Falls, Montana, Las Vegas, Nevada; Missoula, Montana; Omaha, Nebraska; and Tucson, Arizona with 737's.

Frontier took liberation of its first Airbus aircraft -A319 in 2001 and at the same time launched with it DirecTV in-flight television along with another new company livery. Also, Frontier Airlines was the first launch customer of the Airbus A318 in 2003and in mid-April 2005, Frontier with authorization became an all-Airbus fleet, getting away its last Boeing 737.

Frontier Airlines on January 11 2007, signed an 11-year service contract with another American airline- Republic where it was suppose to operate 17 along with a 76 seater Embraer aircraft. Due to certain reasons, the contract couldn’t get materialize and was disposed off in April 2008. Republic Airlines started 11 aircraft for Frontier Airlines, with the remaining six were expected to join the fleet by December 2008. With the amalgamation of Republic aircraft, the 'Jet Express' denotation was detached and subsequently, all flights under Republic were sold and branded as "Frontier Airlines, operated by Republic Airlines." The initial market created specifically for the Embraer 170 was Louisville, Kentucky, on April 1, 2007 and service to Louisville was suspended in August 2008 but restarted in April 2010.

Frontier declared in February 2015, that the services to several destinations from Atlanta will be started. In July, Frontier also began declining its service from Washington Dulles International Airport eliminating the airport as a hub city. In August 2015, Frontier Airlines merged with Spirit and Allegiant by removing their toll-free number for customer service and in early 2016, Frontier announced its chief route expansion from airports nationwide including Atlanta, Chicago, Cincinnati, Cleveland, Orlando, and Philadelphia. In June 2016, Frontier restarted its service to Port Columbus International Airport and in May 2017, the airline announced opportunity of new crew base in Las Vegas in the fall 2017 to progress the operational dependability and potentially create new jobs in Las Vegas.