Cooper has not been seen since and it is not known whether he survived the jump. In 1980, an eight year old boy found $5,800 of soggy $20 bills washed up on the banks of the Columbia river. The serial numbers matched those of the ransom money which had been noted to make it easier to track Cooper later.
Cooper escaped from the plane by jumping off the rear airstair with a parachute leading aviation authorities to add stricter measures about the design of planes to prevent it from happening again. In addition, this event caused airports to install metal detectors for the first time.
I have to say the D.B. Cooper mystery is fascinating to myself as well