United Aircraft and Transport Corporation

The United Aircraft and Transport Corporation was formed in 1929, when William Boeing of the Boeing firms teamed up with Frederick Rentschler of Pratt & Whitney to form a large, vertically-integrated, amalgamated firm, uniting business interests in all aspects of aviation—a combination of aircraft engine and airframe manufacturer and airline business, to serve all aviation markets, both civil aviation (cargo, passenger, private, air mail) and military aviation.

With headquarters at Hartford, Connecticut, the holding company controlled the stock of the Boeing Airplane Company of Seattle, the Chance Vought Corporation, the Hamilton Aero Manufacturing Company (a propeller manufacturer), and the Pratt & Whitney Aircraft Company, an aeroengine manufacturer. Sikorsky Aviation Corporation, the Stearman Aircraft Company of Wichita, Kansas, and the Standard Steel Propeller Company were added to United's portfolio shortly thereafter, followed by several more airlines brought into the fold. The airline interests were soon grouped under a new management company known as United Air Lines, Inc. However, the individual airlines (as well as the individual companies held by United) continued to operate under their own names.

After the Air Mail scandal of 1934, the U.S. government concluded that such large holding companies as United Aircraft and Transport were anti-competitive, and new antitrust laws were passed forbidding airframe or engine manufacturers from having interests in airlines, and United Aircraft and Transport broke into three separate companies. Its manufacturing interests east of the Mississippi River (Pratt & Whitney, Sikorsky, Vought, and Hamilton Standard Propeller Company) were organized as the United Aircraft Corporation (now United Technologies Corporation), headquartered in Hartford with Rentschler as president. The western manufacturing interests (including Northrop Aviation Corporation, formerly Avion Corporation), were folded into Boeing, headquartered in Seattle. United Airlines became a separate company.