Passengers check in for flights with United Airlines at Chicago O'Hare International Airport. United, American and Delta now offer no-frills "basic economy" fares.
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United Airlines planes sit on the tarmac at San Francisco International Airport on July 8, grounded by a computer glitch. Some 3,500 United passengers around the world were delayed.
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A United Airlines 747-400 taxis at San Francisco International Airport in 2011. A group of flight attendants have filed suit against the airline to contest their firing over their handling of a perceived safety threat.