United Air Lines, Inc., is the world's largest airline with 86,852 employees (which includes the entire holding company United Continental Holdings

United Continental Holdings

United Continental Holdings, Inc. , is a publicly traded airline holding company, incorporated in Delaware with headquarters in the United Building in Chicago, Illinois. UCH owns and operates United Airlines, Inc. and Continental Airlines, Inc. both of which use the trade name United Airlines...

 and 702 aircraft. It is a subsidiary of United Continental Holdings

United Continental Holdings

United Continental Holdings, Inc. , is a publicly traded airline holding company, incorporated in Delaware with headquarters in the United Building in Chicago, Illinois. UCH owns and operates United Airlines, Inc. and Continental Airlines, Inc. both of which use the trade name United Airlines...

, Inc. formerly, UAL Corporation

UAL Corporation

UAL Corporation is the former name of United Continental Holdings an airline holding company, incorporated in Delaware with headquarters in Chicago, Illinois. UAL held a 100 percent controlling interest in United Air Lines, Inc., one of the world's largest air carriers, and is a founding member of...

, with corporate headquarters in Chicago

Chicago

Chicago is the largest city in the US state of Illinois. With nearly 2.7 million residents, it is the most populous city in the Midwestern United States and the third most populous in the US, after New York City and Los Angeles...

. United's largest hub

Airline hub

An airline hub is an airport that an airline uses as a transfer point to get passengers to their intended destination. It is part of a hub and spoke model, where travelers moving between airports not served by direct flights change planes en route to their destinations...

 is Houston's George Bush Intercontinental Airport

George Bush Intercontinental Airport

George Bush Intercontinental Airport, is a Class B international airport in Houston, Texas, serving the Houston–Sugar Land–Baytown metropolitan area, the sixth-largest metropolitan area in the United States. Located north of Downtown Houston between Interstate 45 and U.S. Highway 59...

. United also has hubs at O'Hare International Airport

O'Hare International Airport

Chicago O'Hare International Airport , also known as O'Hare Airport, O'Hare Field, Chicago Airport, Chicago International Airport, or simply O'Hare, is a major airport located in the northwestern-most corner of Chicago, Illinois, United States, northwest of the Chicago Loop...

 in Chicago, Washington Dulles International Airport

Washington Dulles International Airport

Washington Dulles International Airport is a public airport in Dulles, Virginia, 26 miles west of downtown Washington, D.C. The airport serves the Baltimore-Washington-Northern Virginia metropolitan area centered on the District of Columbia. It is named after John Foster Dulles, Secretary of...

, Denver International Airport

Denver International Airport

Denver International Airport , often referred to as DIA, is an airport in Denver, Colorado. By land size, at , it is the largest international airport in the United States, and the third largest international airport in the world after King Fahd International Airport and Montréal-Mirabel...

, San Francisco International Airport

San Francisco International Airport

San Francisco International Airport is a major international airport located south of downtown San Francisco, California, United States, near the cities of Millbrae and San Bruno in unincorporated San Mateo County. It is often referred to as SFO...

, Los Angeles International Airport

Los Angeles International Airport

Los Angeles International Airport is the primary airport serving the Greater Los Angeles Area, the second-most populated metropolitan area in the United States. It is most often referred to by its IATA airport code LAX, with the letters pronounced individually...

, Narita International Airport

Narita International Airport

is an international airport serving the Greater Tokyo Area of Japan. It is located east of Tokyo Station and east-southeast of Narita Station in the city of Narita, and the adjacent town of Shibayama....

 near Tokyo, Newark Liberty International Airport

Newark Liberty International Airport

Newark Liberty International Airport , first named Newark Metropolitan Airport and later Newark International Airport, is an international airport within the city limits of both Newark and Elizabeth, New Jersey, United States...

, Cleveland Hopkins International Airport

Cleveland Hopkins International Airport

Cleveland Hopkins International Airport is a public airport located nine miles southwest of the central business district of Cleveland, a city in Cuyahoga County, Ohio, United States. The airport lies just within the city limits of Cleveland...

 and Antonio B. Won Pat International Airport

Antonio B. Won Pat International Airport

Antonio B. Won Pat International Airport , also known as Guam International Airport, is an airport located in Tamuning and Barrigada, three miles east of the capital city of Hagåtña in the U.S. territory of Guam. It is named for Antonio Borja Won Pat, the first delegate from Guam to the United...

 in Guam.
United is a founding member of the Star Alliance

Star Alliance

Star Alliance is the world's first and largest airline alliance, headquartered in Frankfurt am Main, Germany . The alliance was founded in 1997 by five of the world's leading airlines: Air Canada, Lufthansa, Scandinavian Airlines, Thai Airways International and United Airlines...

, the largest airline alliance in the world, and offers connections to over 1,000 destinations in over 170 countries worldwide.