I've completed the FS2 campaign many times on insane. So I decided to try it again, so here I am playing on insane, turreting with a GTF Perseus against NTF Hercules fighters after avoiding their joust. As the topic is about the campaign and AI, so I won't compare it to multiplayer because I am vehement against shooting player-flown ships. The reason I turret is because I'm flying too fast and can't see my target, or they're too maneuverable or annoying.
I do boost and set engines to maximum occasionally if someone else is shooting me, but usually I blow up when that happens. In an Ares...not so much. Usually when one (hopefully) charges towards me, I ETS max shields and press the button to send power to the front shields, tank and tank until they get into hexa-Kayser range.
In other fighters I don't do that because they're made for running around.