Supersonic is unlikely and the physical stresses of 400-500 NKPH would be brutal. I submit he was no more than 200MPH. Still frightenly fast for the Human frame.
I would love to do it. Just the thought of such free flight freedom is awesome. Likely I would not survivebut perhaps wothr the cost of the trip.
I'm one of those guys who, if I ever fall from great height, I hope to have time to try and see if I can fly. I'm guessin' I would only get the one shot at it.