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He will not be "unhindered" by drag, because this is not merely a function of air density but also velocity. The 1.1% of air will have a drag effect that will oppose gravity linearly (if there are no shock wave effects which will only slow him down even more) as his speed increases. Even at 150,000 meters there is sufficient drag to slow down low earth-orbit satellites -- although they are moving 30x faster than the speed of sound.

The big problem even a small amount of drag can cause him is rotation. As soon as there is enough air to have even "negligible" effects on his radial velocity, he will start to turn, and he will spin very quickly without stabilizers.

Ignoring air resistance completely, the best case calculation says he can hit the local speed of sound (around 300 m/s) when he gets slightly over 116,000 feet. I think 120,000 is more like what he needs, but even there I'm not sure it's quite high enough.

I don't work in the field any longer, but most of my research was done at 10^-6 - 10^-9 atmosphere, so I laughed at 10^-2 as a "strong vacuum." I suppose in some applications it is. "Strong Vacuum" is not a term-of-art in my old field (low energy physics.)

I know Strong Vacuum is not a term in the art - but consider who I was addressing... ;^)

Likewise I know that the atmosphere doesn't end - it just fades away. Compared to parachuting at 20k ft, he is “relatively” unhindered to a huge extent (again considering the audience I was addressing) but there will still be a terminal velocity where drag force equals acceleration due to gravity. IF he reaches his goal - his drag forces will include making a shock wave due to exceeding the local speed of sound.

I know that once a satellite gets down to the “upper fringe” of the atmosphere, the atmospheric drag (as little as it has been) increases rapidly due to the extremely high velocity, and all hell breaks loose!

(How much extra energy goes into the ionization effects? I once saw a space shuttle re-entry at about 3AM near Navasota TX. The orange trail persisted across the entire night sky, until well after the shuttle disappeared into the horizon's haze. WOW was that neat!)

A satellite may have been in really low LEO for weeks, but about 30 minutes after it “hits the fringe”, anything that hasn't vaporized is going to hit the ground (or water) somewhere!

Of course, at its terminal velocity...

Regards rotation - experienced skydivers clearly steer with their arms and hands, legs and feet, and general posture. As soon as there is enough speed to generate some noticeable drag (force), he can hopefully stabilize his fall position. I presume he will try to go headfirst to maximize his terminal velocity.

BUT at near 700+ MPH in the low air pressure environment he will be in - holy mackerel! If he DOES spin up - or something DOES “flutter” - or he tumbles - etc. - he may be pulverized. I totally HOPE not, but the possibility exists.

Best Wishes for good luck to him...