Andrew Ames said no hazards were found aboard the plane that landed about 1 p.m. at Reagan National Airport. Authorities swept the plane for explosives including the luggage and interviewed the 44 passengers. Airport police took the person who made the threat in Dayton to a mental health facility, where the person was expected to remain overnight, said Special Agent Michael Brooks, an FBI spokesman in Cincinnati.
No charges had been filed as of Sunday evening and there are no other suspects, Brooks said.
"We have no reason to believe anyone else was involved," he said.
The threat shut down the airport for about 20 minutes. US Airways Flight 2596 was moved away from the gate after landing, the FBI said.
Airport operations were back to normal, although some US Airways flights were delayed because the affected flight was taken to an area used by the airline, Metropolitan Washington Airports Authority spokeswoman Courtney Mickalonis.
The plane was close to Reagan National at the time the threat was received, so officials allowed it to proceed to Washington, FBI spokesman Andrew Ames said.
All of the passengers got off safely.