I have a suggestion for anyone here who really, really wants to kill or severely maim himself: just get on a motorcycle that doesn’t have a fairing, get it up tp 90 mph, and try, just try to stand up on the foot pegs without being torn off by the wind. You couldn’t do it. The force of the wind increases exponentially as your speed increases. That force will keep anybody from flying this invention at any speed much over 35 or 40 mph.
This guy can go 200km/h. That's probably 300 or 400 mph converted.
I did some National hare&hound races after my motocross day were over. Lots of fast fire roads at speeds of 80-90 mph. I stood the whole time in a somewhat crouched position. Never felt like I was going to get blown off. You do squeeze with your legs. I roadraced super bike for a time. At the end of a straight away when you reached you braking reference, you would, pull the clutch in, apply both brakes really hard, and sit straight up. You sit up to use the wind to help slow you down. This happen many time at speeds over 150mph. I never felt I was going to blow off the back of the motorcycle.