United Airlines is one of the largest airlines in the world, with 86,852 employees (which includes the entire holding company United Continental Holdings) and 721 aircraft. It was the brainchild of William Boeing and emerged from his consolidation of numerous carriers and equipment manufacturers from 1928 to 1930.
United Airlines was the creation of aviation pioneer William Boeing who started out in the airplane business in 1916. His Boeing Airplane Company, as it was then called, achieved the first international postal delivery in 1919 and he went on to establish United Aircraft Corp. in 1928. It was this UAC that acquired mail and passenger service operator Pacific Air Transport on 1 January 1928, then, renamed Boeing Aircraft & Transport Co., merged with Pratt & Whitney Aircraft in early 1929 to form United Aircraft and Transport Corporation (UATC). UATC acquired America's first scheduled passenger services carrier Stout Air Services on 29 April 1929, the nation's first scheduled service (mail only) operator Varney Air Lines in early 1930 and, finally, National Air Transport (a large Chicago-based mail-only carrier) on 7 May 1930. On March 28, 1931, UATC formed the corporation United Air Lines, Inc. to manage its airline subsidiaries. Thus United Airlines makes the claim to be the oldest commercial airline in the United States by dint of its Varney acquisition.
Varney was founded by Walter Varney in Boise, Idaho. Varney's chief pilot, Leon D. "Lee" Cuddeback, flew the first contract air mail flight in a Swallow biplane from Varney's headquarters in Boise, Idaho, to the railroad mail hub at Pasco, Washington, on April 5, 1926 and returned the following day with 200 pounds of mail. Varney Airlines' original 1925 hangar served as a portion of the terminal building for the Boise Airport until 2003, when the structure was replaced.