United Airlines, Inc., commonly referred to as
United, is a
major American airline headquartered in
Chicago,
Illinois. It is the world's largest airline when measured by number of destinations served. United operates a comprehensive domestic and international route network, and has significant presence in the Asia-Pacific region. In the late 1920s, just prior to the use of the United Airlines name,
The Boeing Company, currently one of the world's largest aircraft manufacturers, operated a predecessor airline.