Question

Why don't jet aircraft fly in the Troposphere?

Answer 1

Answer:

because of friction......................

Answer 2

Answer:

As an airplane flies higher in the sky the air density and air pressure decreases. Airplanes and jets that fly at high altitudes must be pressurized to account for these changes. The “sweet spot” of flying is regarded as between 35,000 and 42,000 feet – too high and the oxygen becomes too sparse to fuel the engines, too low and the air resistance is greater. This optimum height is linked to the usual weight of a commercial jet – that is, heavier planes would fly lower, and lighter higher.