ATA Airlines, Inc. – formerly known as American Trans Air and commonly referred to as ATA – was an American low-cost scheduled service and charter airline based in Indianapolis, Indiana. ATA operated scheduled passenger flights throughout the U.S. mainland and Hawaii, Puerto Rico, and Portugal as well as military and commercial charter flights around the world. In its early days, the airline flew charters on a worldwide basis and had bases in Chicago, Detroit, New York, Indianapolis, Oakland, and Milwaukee. Later, when it entered scheduled service, the airline maintained focus cities at Chicago Midway International Airport, Honolulu International Airport, and Oakland International Airport.

World Airways, Inc. was an American airline headquartered in Peachtree City, Georgia in Greater Atlanta. The company operated mostly non-scheduled services but did fly scheduled passenger services as well, notably with McDonnell Douglas DC-10 wide body jetliners. World Airways ceased all operations on March 27, 2014.