A passenger jet almost collided with a drone above Florida earlier this year, highlighting the dangers posed by a growth in popularity of remote-control aircraft, the US air safety regulator said.
The pilot reported seeing a small, unmanned aircraft very close to his plane while preparing to land at Tallahassee Regional Airport, said Jim Williams, manager of the Federal Aviation Administration's Unmanned Aircraft System Integration Office.
"The airplane pilot said that the [drone] was so close to his jet that he was sure he had collided with it," Williams said at an industry conference.
The plane, operated by Bluestreak Airlines, a subsidiary of American Airlines, did not appear to be damaged when it was inspected after the March 22 incident, Williams said.
But the incident served to highlight the risk posed by remote-control aircraft, he said.
"The risk of a small [unmanned aircraft] being ingested by a passenger airline engine is very real," Williams said. "The results could be catastrophic."
The FAA bans the commercial use of remote-control aircraft, or drones, in the United States but is under growing pressure to permit their broader use. Hobby and many law-enforcement uses are already permitted.
Last year, the agency began establishing sites where businesses could test commercial uses for unmanned aircraft. Two of the centres have started working ahead of schedule.
"The FAA is working aggressively to ensure the safe integration of unmanned aircraft systems into the national airspace," the agency said.
The March incident was reported to the Tallahassee control tower by the pilot for Bluestreak Airlines, a US Airways commuter carrier. US Airways is part of American Airlines.
The plane, a Bombardier CRJ-200, was travelling from Charlotte, in the state of North Carolina, to Tallahassee.
It was at 700 metres and about eight kilometres from the airport when it encountered the remote-control aircraft.
The FAA investigated but could not identify the pilot of the drone.
American Airlines said it was "aware of the published report alleging an incident with one of our express flights and we are investigating".
The airline said it would share any information with the FAA and would not comment further.
In his speech to the Small Unmanned Systems Business Expo in San Francisco, Williams also showed videos of several drone accidents, including one in which a drone crashed into a crowd during the running of the bulls in Richmond, Virginia, last autumn.
The crash was caused by a battery failure and resulted in minor injuries, he said.