Dan Cooper is the pseudonym of an unidentified man who hijacked a Boeing 727 aircraft in United States airspace between Portland and Seattle on the afternoon of November 24, 1971.
The man purchased his airline ticket using the alias Dan Cooper but, because of a news miscommunication, became known in popular lore as D. B. Cooper. He extorted $200,000 in ransom 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.