On the eve of Thanksgiving, 1971, a nondescript, 40-something man who called himself Dan Cooper approached the airport counter and bought a one-way ticket for the short flight from Portland to Seattle.

Cooper -- an alias spawned by the media -- remains the only unsolved plane hijacking in the history of the United States.

After the aircraft departed, Cooper handed the flight attendant a note.

After getting a glimpse of the mass of wires in his briefcase, the badly shaken flight attendant wrote down his demands -- four parachutes and $200,000 -- and brought them to the captain as instructed.

When the plane landed in Seattle, Cooper let the 36 passengers go in exchange for the money and parachutes, brought on board by the FBI.

But somewhere between Seattle and Reno, Nevada, Cooper jumped out of the rear door of the Boeing 727 and into the bitterly cold winter night?

"He's a guy who presented himself in a James Bond-esque sort of manner," said researcher Eric Ulis, whose own quest to resolve the Cooper mystery was the subject of a History Channel documentary.

FBI investigators examined many intriguing profiles, like that of Barbara Dayton, an amateur pilot and transgender woman who allegedly confessed to her friends; of Lynn Doyle Cooper, whose niece became convinced of his involvement after he showed up bloody and battered to Thanksgiving dinner that year; and of Sheridan Paterson, a World War II veteran interviewed by Fryar.

Cooper thus would have landed miles from the vast search area