Question

while flying why do jet planes leave a white trail in the sky ?

what is the significance of the ozone layer ?

Answer 1

At high altitude, jet stream produce hot and humid exhaust. As hot exhaust gases escape from it, the water vapour in the fumes hits the extremely cold air present at high altitude.This cold air causes the vapour to condense, that means the water vapour turns into tiny water droplet or freezes.This tiny water droplets and mixture of ice crystal make up the white trail in the sky.