United Airlines is a major American airline company which headquarters is situated in Chicago. It was founded in 1926 as Varney Air Lines but later the name changed to Boeing Air Transport. It is also member of Star Alliance. United Airlines is the largest airline in the world as it covers largest number of destinations in entire world. It offers air services for 1000 destinations in 170 countries and about 700 aircrafts are operated by it. It has strong international route network and 10 international hubs in which George Bush International Airport is the largest hub. It is combination of various airlines which include Capital Airlines, New York Air, Arizona Airways, National Air Transport, Air Micronesia, Pacific Air Transport, Varney Air Lines, Pan American, World Airways Challenger Airlines etc. The logo “U” is used on its aircrafts.