I'm not entirely sure why one would pick a water dragon currently as regular dragons are able to fly just fine underwater!

It may play better to make dragons leave their flying state and instead attempt to walk/swim slowly while in the water. Jumping from the surface would allow flying out of the water to prevent getting stuck out in the ocean.

This issue will be a "crossover" of the AI overhaul as well as a swimming feature I have planned. Stay tuned.

Yeah in 0cccf07 it looks like the separated logic for starting flight vs continuing flight makes it so dragons don't stop flying if they hit water.

From what I see on 1.18 they do still prioritize swimming/floating over following and kick off their riders though. If you're seeing something different, let me know the version you're on so I can test and maybe fix.

I would put back the flight cancel, but I actually noticed a bug that causes the dragon's ai to bug out until they next touch ground if I do. Since that's an actual bug, I'm going to hold off. If I can find an easy fix I will put it together, but no promises since the whole ai is going to be rewritten anyways and I'd rather support kay9 with that.

I think this is a good candidate for a feature as part of that larger ai overhaul. I think it was already planned to only allow water dragons to swim underwater and force all other breeds to float to the surface as part of that.