Yeah, you nailed it: this is the D.B.Cooper case and the Vortex in a nuttshell. Then there is also the TB money find which doesn't answer any questions but only makes things more bizarre and complicated.
This case, and the lack of evidence to work with, is so frustrating but at the same time it is the reason why so many people are intrigued and obsessed with it. It is a double-edged sword.