An Air Canada plane with 140 people on board had a near-miss at San Francisco airport after it came close to landing where four other aircraft were waiting to take off.
US Federal Aviation Administration (FAA) officials are investigating after the passenger plane narrowly avoided colliding with jets on the ground.
The pilot of the Airbus A320 inadvertently lined up to land on Friday night on a taxiway that runs parallel to the runway.
An air traffic controller ordered the jet to pull up and circle for another approach, and it landed without further incident.
According to an air traffic control audio recording posted online, a pilot with United Airlines who was waiting on the taxiway said the plane "flew directly over us".
Air Canada has launched its own investigation into Flight 759 from Toronto, which had 135 passengers and five crew members on board.
Safety experts said it is rare for planes to land on a taxiway instead of a runway, and when it happens it usually involves small planes at smaller airports.
Taxiways do not have the same distinctive markings that appear on runways.
It wasn't immediately clear how close the plane came to disaster, with FAA spokesman Ian Gregor only giving basic details, citing an ongoing investigation.
Earlier this year, actor Harrison Ford flew over an airliner and landed his small plane on a taxiway in Southern California.
In December 2015, an Alaska Airlines Boeing 737 landed on a central taxiway at Seattle-Tacoma International Airport. No one was injured.
Aviation-safety consultant Todd Curtis called the incident "a serious event since a landing on an active taxiway could lead to a catastrophic accident”.
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