United Airlines is a major U.S. airline, servicing more destinations world-wide than any other airline. United Airlines has over 85.000 employees and is a subsidiary of United Continental Holdings, Inc. formerly, UAL Corporation, based in Chicago. United's most important hub is George Bush Intercontinental Airport in Houston. United is a founding member of the Star Alliance.
United Airlines has its roots in the Varney Air Lines air mail service of Walter Varney. In 1926 the airline flew the first schedule airline service in the country's history.
During the September 11, 2001 terrorist attacks, two of hijacked airplanes were United Airlines aircraft. An airline industry slump, coupled with economic hardship, increasing oil prices, and higher labor costs, led to the company losing $2.14 billion in 2001.
In 2011 United merged with Continental Airlines.