History. United traces its roots to Varney Air Lines (VAL), which Walter Varney founded in 1926 in Boise, Idaho. Continental Airlines is the successor to Speed Lines, which Varney had founded by 1932 and whose name changed to Varney Speed Lines in 1934.

United Airlines was not originally a single entity but rather the result of a massive 1931 merger of several pioneering aviation companies under the United Aircraft and Transport Corporation (UATC). Before the "United" branding became the sole identifier, the constituent parts included Boeing Air Transport (formed in 1927), Varney Air Lines (formed in 1926 and considered the oldest "ancestor"), Pacific Air Transport, and National Air Transport. These companies were consolidated to manage the various airmail and passenger routes across the United States. Following the Air Mail Act of 1934, which prohibited the common ownership of aircraft manufacturers and airlines, UATC was broken up, and the airline portion officially became United Air Lines. This period is often cited as the birth of the modern airline industry structure, transitioning from smaller mail carriers to a unified transcontinental passenger service provider.