Ok, it's the year 2016. You are in a little Cessna 150.
You're plane isn't pressurized because it will implode,
so you're wearing a pressurized body suit. You have
an oxygen mask. You plane is powered by a very
powerful brushless electric motor supplied by a 20lb
carbon nanotube source that is basically limitless.
Your powerplant is equivalent to 700hp in an LSA.
The electric motor and cabin are heated.

How high can you fly? 95,000ft?

This will soon be a real consideration.

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Mark