A 75

I'm AFB righ now, so someone please correct me if I'm wrong.

But in the Draconomicon (i think), there's a passage on how Dragons like to cast Fly on themselves, sacrificing speed for maneuverability. Unfortunately, I don't remember if there's any mention of the Dragons still being able o use their regular Fly Speed, however, this passage makes it clear that the Speed and Maneuverability are locked per Fly Speed.

As in, the Dragon can't use his higher fly speed in conjunction to the better maneuverability from the Fly spell