There's a ton of threads and opinions here, and plenty of youtube reviews as well. A good handfull of people have the Pro and the Air, and most of them seem to prefer the Air. That said, I think it is really about what you want to do. If you like to just "fly" the added range and battery life of the Pro (and particularly the Platinum) may be best. If you really are using it as a flying camera, the smaller size, slightly better camera, and few extra features (rear avoidance sensors, APAS, couple of extra camera modes) may make the air a better choice.
My P3 still works great, so I went for the Air to have something small to bring around, and could still use the P3 if I really needed significant range (although I have not busted out the P3 since getting the Air)