A set of atherial wings or something similar that functioned as a mount would be nice as long as they are kept simple. Though I could see elemental wings as an expansions primal ex reward mounts. Altogether I would like and use something like this, especially if they add DBZ style unsupported flight.

Adding in personal flight mechanics similar to Aion or it's ilk would be a big change in the story, last I checked cats don't fly though a lala will if you kick hard enough.

Air combat would most likely be similar to swimming in other games. In short, no thanks.