Why do Aeroplanes need to go so high to travel?

Question

I hope I convey my point probably, but why do planes go so many thousands of feet in the air? Is it faster that way, or could they achieve similar flight times at a lower altitude?
Does it have something to do with the curvature of the earth?

In: Engineering

Answer 1

If you could fly like superman but just your normal human self, would you rather:

Fly at hundreds of miles an hour face first through an infinite ball pit of those hard plastic balls?

Or through an infinite “ball pit” of bubbles that pop on contact?

The higher the altitude, the less dense the air is. Easier to fly through as there is less stuff hitting you in the face.