That's also my impression. And I was just sitting in a lousy Cessna ...

I dunno however if one could hear one's own machine gun firing as the Cessna had none installed

That's why I added the option gun sounds.

If you want to know if a fighter pilot could have heared a pilot behind him ask a veteran. Oh wait this was done many times. Not one of all accounts that I have read ever mentioned that they could hear other planes with their own engine running. In contrary they all concorde in that they could not hear it.

I however concede that the first option is badly phrased. Blame it on me not being perfect in English.