The "... in Popular Culture" section is large enough to have been spun off into it's own article on Wikipedia: https://en.wikipedia.org/wiki/D._B._Cooper_in_popular_cultur...

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.