While treseritops' explanation is valid. I think that that is more related to movement from idle to begin with. Another part I can fill in with a different perspective: traction. Anyone here that has learned to drive (from a decent instructor) is told to brake before turns and accelerate in the turns(not floor the pedal mind you...). This is for the simple reason that if you don't apply traction in the direction you wish to go, the car will still try to go in a straight line. Turning the airship in GoI is basically the same thing, just a little different. By staying forward, you are turning at max speed (or whatever speed you set) giving you the longest turning arc because the ships turn rather slowly. By going neutral you lose traction, which means you are going to go in the direction you were going before you turned your ship; this allows you to strafe. The third is reversing, you apply traction in the opposite direction you were originally going, slowing down the vessel and thus allowing a much sharper turn. In that turn of course there's a moment where the throttle should be set to forward once more as to not lose distance.
As such of course, there is no turning faster except for using a phoenix claw. But out of all the options available, there is no real best, just look at what you wish to achieve and pick the tool to do it.
