Well, one man did do that, literally. On Thanksgiving Eve in 1971, Dan Cooper, not his real name, blithely stepped off the back stairway of a Northwest Orient Boeing 727 at an altitude of about 10,000ft. Equipped with two parachutes and clasping a bag of $200,000 in ransom money, he hurtled through the rain clouds to the rugged terrain of Washington State below.

In these post-September 11 days of international terror threats, what happened that night seems almost like an innocent caper. No one was murdered or even grazed and the sum of missing money seems almost paltry. Yet it was an act of derring-do that quickly entered modern American folklore. Songs and books were written about it and a film was shot starring Treat Williams as Cooper. More than that, the seizing of Northwest Orient Flight 305 remains the world's only unsolved hijacking.