Why do planes fly at high altitude even across the oceans, when flying at lower altitudes require covering a shorter distance?

Question

Why do planes fly at high altitude even across the oceans, when flying at lower altitudes require covering a shorter distance?

In: Engineering

Answer 1

Is not as much further as you probably think. The difference between the equatorial circumference at sea level and at 1 foot above sea level is less than 7 feet.