Sleeping Passenger Left Aboard Plane in Philadelphia

PHILADELPHIA -- Airline officials are trying to figure out how a sleeping passenger was left aboard a flight that landed in Philadelphia for several hours before being discovered by a cleaning crew.

According to police and the Transportation Security Administration, the passenger didn't wake up when her United Express flight from Washington D.C. landed shortly after midnight Tuesday. It wasn't until nearly 4 a.m. that a cleaning crew discovered the sleeping woman.

United Airlines says they're working with a regional partner carrier to determine why the plane wasn't cleared upon landing.