Gamer, SHIFT M wont work either if you already use the mouse for flying!
Besides, in a fight, mouse look wont help you at all, sonce you need both hands to control plane. Best is to use the snap (f7) or the instant (f9) views on your numpad numbers/hatswitch (if you got a joystick). You have 8 way views, a "look up" - combine those and you get 17 views total. Set those up with good head positions and you have the perfect basis for a good Situational Awareness of all that happens around you.