DB Cooper remains the only ever successful plane hijacker in U.S. history and for this the FBI has kept the case open for 40 years. There is now some evidence that he did survive his jump into the darkness, yet his motives remain unclear.
The 10,000 bank notes Cooper received from the FBI were easily traceable via their serial numbers. Cooper was an exceptionally calm and professional thief, and one can only assume he knew he could never spend the money. The $20 bills never reentered circulation, nor were they ever found. No sign of altered serial numbers in the 1969 “L” series the bills originated from were detected in the years following the heist.
I kept wondering why Cooper took such incredible risks for no gain until it became clear that what he was seeking was a departure, one he could only achieve by entering the darkness. In that he was indeed the most successful hijacker in U.S. history.