A ground stop has been issued for San Francisco International Airport (SFO) in California, the Federal Aviation Administration (FAA) announced in an advisory on Sunday.
The agency did not immediately provide further details regarding the disruption. The groundstop was lifted shortly after it was issued.
San Francisco International Airport did not respond to a request for comment regarding the situation.
The busy hub served more than 54 million passengers in 2025, according to its official website, and is a major operational base for carriers including United Airlines, Air Canada, and American Airlines.
The FAA had previously stated in March that it would implement new safety restrictions at SFO, which were expected to limit certain landings and lead to considerable delays.
Earlier this year, a new FAA rule reduced San Francisco’s airport from 54 plane arrivals per hour to 36. It is not yet clear if any flights will be cut.
A deadly runway crash between an Air Canada jet and a fire truck at New York’s LaGuardia Airport in March is the latest air-traffic safety calamity, but the aviation administration said the rule change was unique to SFO and was not triggered by broader safety concerns.
The San Francisco safety concerns are unique to that airport because of how close the parallel runways are and how complicated the airspace is with several surrounding airports.
FAA spokesman Ian Gregor said officials decided that SFO’s longstanding practice of landing two planes at the same time on closely spaced parallel runways that are just 750 feet apart — along with congested airspace — was too dangerous. He could not say why the practice had been allowed.
SFO operates on two sets of parallel runways. The north-south runways are out of commission for six months for a repaving project that accounts for nine of the 18 flight-per-hour reductions.
The rule change affects the remaining nine flights.
