The Federal Aviation Administration says it’s limiting how many flights can land at San Francisco International Airport. Those proposed changes would have affected a third of all the flights that landed there last year, a Chronicle analysis found.
The new restrictions on the airport would prevent two planes from landing in parallel on the airport’s longer east-west runways, reducing the number of flights that are able to land per hour. Separately, SFO is also renovating its two shorter runways, further restricting that number. Together, the FAA regulations and the six-month construction project mean that the most flights that can arrive per hour is 36, down from 54, potentially creating delays.
In 2025, 31% of all arrivals at SFO landed during hours that had more than 36 landings, according to a Chronicle analysis of flight operations data. On average, that meant that roughly 4 hours a day were above the new landing cap.
There was some fluctuation depending on the month. Last year, the colder months — January, February, March, November and December — tended to have fewer hours over the new cap each day than months in the middle of the year. (In previous years, though, the busy holiday season has seen the highest share of crowded hours, though the total volume of flights has risen each year since the pandemic.)
Similarly, Mondays and Fridays tended to have more hours over the limit than other days of the week. Evenings — between 4 p.m. and 9 p.m. — were the time of day that most frequently have hours over the cap.
Still, nearly every single day in 2025 had at least one hour that exceeded the 36 hour cap — which means that, if flight patterns stayed exactly the same, nearly every day during the next six months of runway construction could be impacted in some way.
SFO officials said the new restrictions mean that up to a quarter of arriving flights could be delayed by 30 minutes or more. Parallel landings were already banned during foggy or otherwise inclement weather, which, when paired with runway construction in previous years, has caused delays to spike.
So far, however, SFO seems to have avoided disaster. The share of flights arriving at the airport that were delayed were relatively normal Tuesday and by Wednesday afternoon, according to a Chronicle review of FlightAware data.
SFO, the FAA and airlines have told the Chronicle that they were reviewing the new guidelines to determine how to reduce delays.