Founded in 1973 under the name of American Trans Air, ATA Airlines (TZ) was mainly a low-cost airline and had flown passengers throughout the US mainland and Hawaii. Along with non-stop flights from Chicago Midway International Airport, Honolulu International Airport and Oakland International Airport, it also had military and commercial charter flights around the world. Conceived with the idea to provide aircraft for the Ambassadair travel club, ATA Airlines had a fleet comprising of 29 airplanes.
Following the closure of its main hub in Indianapolis International Airport in 2005, ATA Airlines operated from Chicago Midway International Airport which also closed down in 2008. It had a frequent flyer program called ATA Travel Awards and had flown million passengers to their destinations within Mexico and the United States. The airline finally ceased operations from April 3, 2008.