United Airlines Holdings, Inc.

United Airlines was formed in 1931 as a subsidiary of United Aircraft and Transport Corporation to manage a group of airlines controlled by William Boeing, including Boeing Air Transport, National Air Transport, Pacific Air Transport and Varney Air Lines, all of which held U.S. Air Mail contracts. Of its predecessor companies, the first to commence cargo ( airmail ) operations was Varney Air Lines on April 6, 1926, a date United later celebrated as its centenary. The 1934 Air Mail scandal led to the dissolution of the parent corporation, resulting in the separation of Boeing, United Aircraft (now RTX ), and United Air Lines, all of which continued as independent major American companies.

As an independent company, United expanded rapidly. In 1933, it introduced the Boeing 247, the first modern airliner, enabling non-stop transcontinental travel. During World War II, United modified the aircraft for military use and transporting supplies. After the war, United capitalized on the aviation boom, and in 1961 merged with Capital Airlines, briefly becoming the world's second-largest airline. United was a major proponent of airline deregulation in the 1970s and would ultimately benefit from the post- deregulation decline of Pan American World Airways acquiring Pan Am's Pacific route authority in 1985, its London Heathrow operation in 1991, and its Latin America and Caribbean network in 1992. In 1997, United was one of the five airlines to launch Star Alliance, the first global airline alliance.

United suffered significant losses during the September 11 attacks, when two of its aircraft—a Boeing 757 and a Boeing 767 —were hijacked and deliberately crashed. Already facing financial difficulties, the airline was further affected by the post-attack economic downturn and filed for bankruptcy in 2002. United emerged from bankruptcy in 2006 after restructuring and, in 2010, merged with Continental Airlines, creating one of the world's largest airlines.