Dan Cooper is the pseudonym of an unidentified man who hijacked a Boeing 727 aircraft in the airspace between Portland and Seattle on the afternoon of November 24, 1971.
He extorted $200,000 in ransom (equivalent to $1,260,000 in 2019) and parachuted to an uncertain fate. Despite an extensive manhunt and protracted FBI investigation, the perpetrator has never been located or identified. It remains the only unsolved case of air piracy in commercial aviation history.
Many FBI agents are of the opinion that Cooper probably did not survive his high-risk jump, but his remains have never been recovered.
Numerous theories of widely varying plausibility have been proposed over the years by investigators, reporters, and amateur enthusiasts.