A Delta Airlines Boeing 767-300, registration N394DL performing flight DL-221 from Manchester,EN (UK) to New York JFK,NY (USA), was enroute over the Atlantic Ocean when a passenger went to a lavatory and found a loaded gun. The passenger handed the gun to cabin crew, who in turn returned the weapon to the owner, a female US Air Marshal, who had forgotten the weapon in the lavatory. The aircraft continued to New York for a safe landing without further incident.
Incident: Delta B763 over Atlantic on Apr 6th 2017, lavatory or armoury