A man who stole an empty passenger plane from Seattle airport and then crashed it was an airline worker with full credentials, authorities say.
The man, named by US media as Richard Russell, took off late on Friday, forcing the airport to close while two fighter jets gave chase.
After making "incredible manoeuvres", he crashed the plane and was killed.
After take-off he performed at least one dramatic roll, pulling the aircraft up just metres from the water before gaining altitude again.
The 76-seat, twin-engine turboprop Bombardier Q400, belonging to Horizon Air, took off from Seattle-Tacoma International Airport at 19:32 local time (02:32 GMT).
Officials say the man used a pushback tractor to first manoeuvre the plane 180 degrees from a maintenance location into the correct position for take-off.
The North American Aerospace Defense Command (Norad) issued a statement saying that two F15 fighter jets were launched from Portland to intercept. A number of videos showed them following the passenger plane, which was flying in an erratic manner.
Norad said the F15s were "working to redirect the aircraft out over the Pacific Ocean when it crashed on the southern tip of Ketron island", about 30 miles (48km) south of the airport.
The flight lasted 90 minutes and the crash site is on Ketron Island, a sparsely populated area in Puget Sound.
"At this time, we believe he was the only one in the aircraft but of course, we haven't confirmed that at the crash site," said Jay Tabb, chief of the FBI's Seattle division.
Richard Russell worked as a ground-service agent for Horizon Air
A former airline colleague of Russell described him as a "quiet guy".
"He was well liked by the other workers," Rick Christenson told The Seattle Times. "I feel really bad for Richard and for his family. I hope they can make it through this."
Transcripts of his conversation with air traffic control reveal a man who appears surprised about his feat, who is unclear as to the full operations of the plane, who has no intention to hurt anyone and who ultimately apologises to his loved ones, saying he is "just a broken guy".
Courtesy: BBC News