United Airlines (UA, Chicago O'Hare) has announced it will accelerate the retirement of its remaining B747-400s from scheduled service with the type's last commercial flight now slated for the final quarter of the year. Previous plans had called for a late 2018 phase out.

The carrier's president Scott Kirby said in a press release issued Wednesday, January 11, that the B747-400 was no longer a cost-effective option for the long haul scheduled market.

"Today, there are more fuel-efficient, cost-effective and reliable widebody aircraft that provide an updated in-flight experience for our customers travelling on long-haul flights," he said. "For these reasons, we’re saying farewell to the Queen of the Skies, which has been part of our fleet since we first flew the aircraft between California and Hawaii in 1970."

According to the ch-aviation aircraft database, United operates twenty B747-400s on scheduled flights from their San Francisco base to Beijing Capital, Frankfurt International, Hong Kong International; London Heathrow; Seoul Incheon, Shanghai Pudong, Taipei Taoyuan, and Tokyo Narita.

They are also used for charter flights that are carried out for and on behalf of the US military to select points across the United States as well as the Middle East and Europe.