What I'm having trouble figuring out is how exactly an army of Giants would fight against an army of Dragons. Do the Giants hang on the ground and throw huge boulders as the Dragons try to come within breath-weapon range? Do the Giants ride into battle on the backs of Rocs (or other oversized birds)? Do the Giants have some kind of storm-based magic that lets them fly around for mid-air battles? Some combination of the above?
Basically does anyone have any ideas for cool/sensible strategies for a group of Giants to successfully fight against a group of Dragons?