As I remember it from 2A the hissing noise of air friction was all I could hear when in cruising flight. I don't recall hearing the sonic boom. I could hear the frequency range of the engines during taxiing, takeoff roll and the climb. It didn't feel much different than any other (jet-powered) airplane when seated in the front. Your question, as I perceive it, relates to Einstein's concept of relativity. That's why it matters where you observation point is (on the ground or inside the moving airplane).