It only works when enabled. (Which usually means offline, h2h, or in KOTH events)
To enter the god view mode, hit F5'
Hold down directx button 2 to move forward, button 3 to move back. While holding these buttons, your throttle controls the speed, and stick and rudders control pitch roll and yaw. (it's like flying a real UFO)
if you dont have directx buttons mapped, you can set buttons or keys for it in the view section of the controls.