In November 1971 a man known as Dan Cooper hijacked a commercial airline and was never seen again.
The mystery has baffled cops in the American states of Oregon and Washington in the north west for more than 50 years.
Little is known about the hijacker or where he ended up but he did escape with a $200,000 (£160,000) ransom which is more than $1million (£802,000) today.
