laughed so hard at this <| sep |> It ' s standard abuser logic I didn ' t want to hurt you , you made me do it ! <| sep |> United Airlines is a major American airline headquartered in Chicago , Illinois and by the measure of destinations served , it is the largest airline in the world . The airline has a significant presence all around the world and due to its extensive route network , it has multiple hubs in the US and one outside the US . In the US they have hubs at Denver International Airport , George Bush Intercontinental Airport , Los Angeles International Airport , Newark Liberty International Airport , O ' Hare International Airport , San Francisco International Airport , and Washington Dulles International Airport . They also have a hub in Guam as well as one at Narita International Airport in Japan . Being the largest airline in terms of destinations served consists of 235 domestic destinations and 138 international destination in 60 countries across the world this include flights served by United Express . United at one point was on the list of the few airlines who touched down in six continents but after discontinuing flights to Nigeria , they no longer served the African continent . In 2010 , United and Continental merged their companies and over the past few years have completely transitioned into one airline . While United was the surviving company , Continental ' s logo is now the one seen on the tail of all United airplanes . United operates a rather large fleet that consists of The Airbus A 319 and A 320 with the A 3501000 set to join the fleet in the next few years . The airline operates mainly Boeing aircraft which include the 737700 , 800 , 900 , and 900 ER with the 737 MAX 9 on order . They also operate the Boeing 747400 , 757 , 767300 , 300 ER , and 400 ER , the Boeing 777200 , 200 ER , and 300 ER , the Boeing 7878 and 9 with the 10 due to join the fleet and the airline also has Embraer E 175 s on order . United Airlines was one of the founding members of the Star Alliance and being that they serve so many destinations , they are a valuable codeshare partner . Outside of Star Alliance they have codeshare agreements with airlines like Hawaiian Airlines , Jet Airways , Island Air , Cape Air and more . United ' s frequent flyer program is called Mileage Plus .