No one knows, and if they do know how to trace him, they are not telling. The FBI is no longer actively pursuing what has been called, one of the most prolonged and most extensive investigations in history.
In 1971, a man who presented himself as Dan Cooper seized a passenger plane from Oregon to Seattle where he freed the passengers in exchange for money. As the nearly empty flight took off with them, he proceeded to parachute out of the airplane with the ransom, and he was never seen again.