1) the first and most obvious one would be to just drop boulders and logs on you from well out of range of your arrows or spells.
2) instead of just flying around all over the place he could be a sneaky stealth dragon and hide behind trees.............if giant transformers can hide behind big trees why shouldnt dragons be able to. imagine the sneak damage multiplier from getting attacked from behind by a dragon
3) ambush. all the dragon has to do is figure out where your going and since its more mountainous terrain you are most likly going to be in valleys. he can set up punji spike traps, trip wires that send boulders rolling down on you, hide behind a big rock until you get close and then pop up and hit you with his dragon shouts etc.
4) the dragon could simply step on you..........hmmmmmm now that i think about it i think that this should be the most obvious one.
5) he could choose to weaken your character with biological attacks. assuming dragons have accurate aim just like birds to then why wouldnt they just bombard your character with dragon poop. at some point your character will get ecoli or some other debilitating bacteria making him easy pickings for the dragon or just any random wilderness monsters.
any others?