Atlanta police spokesman Otis Redmond says foul play is not suspected in the woman's death.
Georgia Bureau of Investigation spokesman John Bankhead says the woman's body was taken to a crime lab for an autopsy.
Delta spokeswoman Susan Elliott says the passenger was found unresponsive early Monday aboard Delta Flight 53, about an hour out of Atlanta and about 11 hours from the time it took off. She says the airline can't identify the passenger.
Bankhead says the FBI is investigating because the death occurred on an international flight.