Aerial combat

[Traith]

So, my group has an upcoming session (3.5) in which we're going to be fighting a battle entirely in the sky.

We're going to be a defending a castle from multiple invading forces, one of which is a flight team. We're planning on intercepting the flight team a few miles away from the castle, which means a typical fly spell may not last long enough to get us there and finish the fight. Also, we can't rely on ground support, considering this is going to be happening right above the heads of the invading army.

We have every core class at our disposal, except for a druid. Our strongest characters are between 7th and 9th level. Anyone have some general help/useful spells for this type of fight?

[Innis Cabal]

Stunning is a great way to screw flying targets. Anything that stops them from flying really. Its a fast, effective way with little to no violence or bloodshed. The best philosophy of aerial fighting is don't. Bring em to the earth.

[Knaight]

The better maneuverability you have, the better off you are. Stay above the other people, directly above them. If they shoot you down they take you down with them, and if they have crappy maneuverability you can predict their motions.

[AtopTheMountain]

Baleful Polymorph.