A major airline is checking its passenger seats after some came loose following take-off on three separate flights.

American Airlines said the incidents occurred on a flight last week between Vail, Colorado, and Dallas-Fort Worth and again on Saturday and Monday.

A spokeswoman said the airline was inspecting eight of its Boeing 757s with similar seat assemblies.

The US Federal Aviation Administration said it was looking into the incidents, which raised questions about safety on the third biggest US airline.

The spokeswoman said the loose seats were not the result of sabotage by workers. American's union employees are unhappy about pending layoffs and cuts in pay and benefits that the company has imposed since filing for bankruptcy protection in November. American accuses some pilots of conducting an illegal work slowdown that has caused a jump in cancelled and delayed flights.

An initial review by American indicated that there could be a problem with the way the seats fit into tracks on the floor of the Boeing 757, but technical teams from the airline "are looking at everything," the spokeswoman said.

Aviation industry experts said publicity about the problem could cause passengers to stay away from American.

PA