American Airlines (AA, Dallas/Fort Worth) has announced it will close its crew base at San Francisco by the end of January 2023 citing efficiency concerns.

"As we look to the future, we expect San Francisco to maintain the same level of flying as it does today, but there are no plans to grow and no future flying prospects based on our current network strategy," the airline said in an internal memo.

The carrier's San Francisco crew base is the smallest in its network and American Airlines has been gradually reducing its footprint at the North Californian gateway, having closed its pilots' base there airport a few years ago. The decision to close the remaining crew base will affect around 400 employees, who will be offered relocation options, although not to its saturated Los Angeles International base.

The decision comes in the wake of a recent Supreme Court ruling which confirmed that airlines with crews based in California must abide by the state's labour laws, which afford employees more generous breaks. American Airlines did not cite the ruling as a reason for its decision.

The ch-aviation capacities module shows that American Airlines is the fourth-largest passenger carrier at San Francisco airport with a 5.8% market share by scheduled weekly capacity (behind United Airlines, Alaska Airlines, and Delta Air Lines) and proffering 198 weekly scheduled departures.