Question

we are able to here the aeroplane sound in morning but at night we are not able to here that sound .
(no swamp like due to sleeping) GIVE ACCORDING YOUR ANSWER ON BASIS OF PHYSICS

Answer 1

At some places or airports, there are rules that keep aircraft higher at night to avoid the noise created by them, so as to meet and fulfill the noise pollution prevention related norms and regulations for that city. It's called a Noise Abatement Procedure or a Noise Mitigation Program etc.;