Wouldn't it be almost lethal to fly in something going that fast?
Only if you hit something not going that fast...
"Wouldn't it be almost lethal to fly in something going that fast?"
Only if was on open cockpit.
With velocity, all things are relative, so to speak. Now the ACCELERATION might be tricky.
Guys went Mach 6+, almost Mach 7 in the X-15, and astronauts go faster to achieve escape velocity. What can harm a person is not speed per se, but sudden acceleration or deceleration. For instance, SpaceShipOne and some tank cannon projectiles both do between Mach 3 and Mach 4. Accelerating like SpaceShipOne doesn't harm people. Accelerating like a tank round would turn people to jelly!
Absent a sudden onset, there's no physiological limitation to how fast you can go (inside something, obviously).
d.o.l.
Criminal Number 18F