United operates an extensive domestic route in the Midwestern and Western United States. United is also prominent in transcontinental, transatlantic, and transpacific service. It is by far the leading US carrier to Hawaii and largest to Asia and Australia.

In 1988, the bilateral treaty with Japan was amended to allow additional routes between the two countries.

United operates a low-cost leisure brand called Ted. The name is taken from the last three letters of its parent United. Ted serves leisure destinations within the U.S.and Mexico with 240+ daily flights. Ted is the only "airline-within-an-airline" left in the U.S. United has announced the discontinuation of its Ted product beginning in the fall of 2008.

United is focusing on its International presence, notably in the People's Republic of China, with nonstop flights to Beijing, Shanghai, Guangzhou (as of June 2009), and Hong Kong from its hubs in Chicago, Los Angeles, San Francisco and Washington, D.C. In September 2007 United was granted a route from SFO to Guangzhou. United has also focused more on Latin America and added new destinations and frequencies to Mexico and the Caribbean.

In May 2008 United called off the merger discussions. Subsequent to the failed merger attempts, and with the oil price increases since '03 in full swing.

On June 19, 2008, CEOs of both United Airlines and Continental Airlines signed a pact which possibly could eventually lead to a merger between the two airlines. The alliance is an agreement to link International networks and share technology and passenger perks. This agreement is basically a "virtual merger" that will include many of the benefits of a merger without the actual costs and restructuring involved. Now that Delta and Northwest Airlines completed their merger, this will release Continental from the SkyTeam contract and allow for the required nine-month notice.