What are the advantages of airplanes flying so high?

Question

If it’s because of wind tunnels that helps push the planes faster, how much slower would they be if they weren’t in those wind tunnels?
If the average flight from NY to London is 7H and 10M what would the flight time be?

In: Physics

Answer 1

Higher altitude means thinner air which means less air resistance which means less fuel needed to push the plane along. Cheaper and better for the environment.