United Airlines officials say a pilot aborted a flight just before takeoff out of concern that sea gulls had struck one of the aircraft's engines.
United spokeswoman Robin Urbanski said Flight 1220 from San Jose to Denver had reached nearly 140 mph on the runway Monday when the pilot called off the flight.
Urbanski said the pilot was able to shut down the engine before leaving the ground and returned to the gate without incident.
The flight was scheduled to depart Mineta San Jose International Airport at 7:12 a.m. The plane was taken out of service while investigators worked to confirm whether birds had hit the engine.
The plane's 97 passengers were booked on a later flight, officials said.