D. B. Cooper is a media epithet popularly used to refer to an unidentified man who hijacked a Boeing 727 aircraft in the airspace between Portland, Oregon, and Seattle, Washington, on November 24, 1971, extorted $200,000 in ransom (equivalent to $1,170,000 in 2015), and parachuted to an uncertain fate.
Despite an extensive manhunt and an ongoing FBI investigation, the perpetrator has never been located or positively identified.
The case remains the only unsolved air piracy in American aviation history.
And another: 30 Rock implies that Kenneth's father was D.B. Cooper. In one episode he's wearing a suit passed down from his late father. The inside pocket of the suit coat is inscribed "D.B. Cooper."
Weirdly, this happened in season 6 episode 10, like the Numb3rs episode.
https://en.wikipedia.org/wiki/D._B._Cooper