United Airlines (UA, Chicago O'Hare) is planning to complete the phase out of its fleet of B747-400s a full two years ahead of schedule Howard Attarian, United's senior vice president for flight operations, has disclosed.

In a letter to United's pilot corps, Attarian said the carrier now planned to end B747-400 operations in 2018 as opposed to the originally prescribed deadline of 2020. United justifies the move on the grounds that their 747 fleet's age (which averages 20.3 years) coupled with dwindling numbers of remaining commercial operators of the type, have rendered support for the type increasingly difficult and expensive.

United's twenty-two B747s are based out of Chicago O'Hare and San Francisco though effective February of next year, those based out of Chicago will be removed leaving the US West Coast as the type's sole remaining base.

The aircraft are used on scheduled passenger flights to Beijing Capital, Frankfurt International, Hong Kong International, London Heathrow, Seoul Incheon, Shanghai Pudong, and Tokyo Narita. The carrier also uses the B747s on US military charter flights.

In terms of replacement aircraft, United has thirty-five A350-1000s on order from Airbus (AIB, Toulouse Blagnac) alongside ten B777-300(ER)s and twenty-five B787-10s due from Boeing (BOE, Washington National)