United Airlines, Inc. is a major U.S. airline headquartered in Willis Tower, Chicago. Founded in 1926 as Varney Air Lines, United operates an extensive domestic and international route network, serving 362 destinations across six continents. A founding member of the Star Alliance, United boasts one of the largest airline fleets in the world, with 972 aircraft. The airline operates from eight hubs, including Chicago-O’Hare, Denver, and Newark. Known for its MileagePlus frequent-flyer program, United offers premium services such as Polaris Business class. The airline is led by CEO Scott Kirby and employs over 103,000 people.