People wait in line at the United Airlines counter at LaGuardia Airport in New York November 25, 2008. REUTERS/Shannon Stapleton

LOS ANGELES (Reuters) - A woman left locked alone in a plane asleep for about four hours after landing at Philadelphia International Airport is suing United Airlines.

Ginger McGuire, 36, is suing for false imprisonment, infliction of emotional distress and negligence, her attorney Geoffrey Fieger told the U.S. newspaper Detroit Free Press.

McGuire fell asleep on a late-night United Express flight from Washington, D.C., to Philadelphia. She failed to wake up after the 50-passenger plane touched down at 12:27 a.m. local time and everyone else disembarked.

A cleaning crew eventually roused her, but she was kept locked in the plane until federal officers were satisfied that she was not a terrorist, said the newspaper.

“We are working closely with our partner Trans States Airlines to investigate the cause and remedy the situation with the customer,” United Airlines spokeswoman Sarah Massier told the paper.

No one at the UAL Corp unit was immediately available for comment. Fieger is a high-profile attorney whose clients have included euthanasia practitioner Jack Kevorkian, and a U.S. soldier who claims the producers of Oscar-winning war movie “The Hurt Locker” stole his story.