The 11:45 a.m. event happened after the Aeromexico jet was cleared on Runway 28R at the airport, which is parallel to Runway 28L. The R stands for right and the L stands for left, Gregor said.
Crew on the Aeromexico jet were "cleared to land on Runway 28R, and correctly read back that clearance. When the plane was about a mile from the airport, air traffic controllers noticed the aircraft was lined up for Runway 28L and instructed the crew to execute a missed approach," Gregor said.
The plane later safely landed, Gregor said. He said the FAA has opened an investigation.
Pilots and safety experts said air traffic controllers did a good job when they quickly redirected the Aeromexico jet at an airport that many pilots say is notoriously difficult to land at. The runways are close together and, unlike at other major airports, planes landing and taking off often share the same runways.
"I would not say there's cause for alarm," said retired airline captain and aviation safety expert John Cox. "The tower, air traffic control, did a very good job. They sent the Aeromexico flight around."
Longtime American Airlines pilot Chris Manno said "it seems a pilot got left and right wrong in their head," Manno said. "The good news is the controller recognized it and the system worked."
An Air Canada flight crew landed in October on one of the airport's runways despite repeated warnings to abort because a controller believed another airplane had not left the area yet.
In July, an Air Canada jet with 140 people on board nearly landed on one of the airport's taxiways where four planes were waiting to take off, prompting the FAA to issue new rules for nighttime landings and control tower staffing at the airport.
"The third incident in six months, it does raise an eyebrow," said Doug Moss, an aviation consultant and airline pilot. "All three incidents were caused by different reasons, but in general the San Francisco airport is somewhat problematic, in that there's a lot of traffic in and out of there, and there's not enough runways. The runways they do have are not separated laterally enough."
He said officials have pushed for years to expand the airport, but there is significant community opposition.
Associated Press writer Juliet Williams also contributed to this report.