United Airlines
Serving every continent (besides Antarctica), United Airlines flies to 73 destinations in the U.S. and another 41 internationally. Formed in 1929 from a merger of Boeing Air Transport and Pratt & Whitney, United is now the largest airline in the world by number of destinations. Its major domestic hubs include Cleveland, Denver, Houston, Los Angeles, Newark, Chicago, San Francisco and Washington, D.C. United’s frequent flyer program, MileagePlus, rewards its members for purchasing travel as well as other products and services from United’s partners, and can be enrolled in at United.com. United recently announced daily flights from Los Angeles to Shanghai.