#27 Dan Cooper
A man, Dan Cooper, in 1975, took a Northwest Airlines flight to Seattle.
During the flight, Cooper gave a handwritten note to one of the flight attendants that reportedly demanded $200,000, a fuel truck for refueling, and four parachutes.
The demands were met, and Cooper permitted all the passengers to get off the aircraft. However, when the flight arrived in Reno, Cooper was nowhere to be found.
Since then, this mystery remained unsolved as Cooper was never heard from ever again, nor were his remains found.