So....I decided to play a Dragonkin. My friend is playing a Pahtra. They came up with the idea...
What would be the mechanics of the Pahtra riding the Dragonkin?
It's not directly covered, PCs riding PCs.
I'd do it so that if you take a move action other than to hover mid air, the rider must also use a move action to hang on. Since you're a dragonkin I'm assuming you'll be going on the same initiative order so you can at least avoid wonkiness there.