I guess its not a priority right now, but they might work on it in the future. An example, SE worked on the Bunny Outfit for males, they finished it for two races, this was a while ago, but during the Shanghai fanfest they confirmed that the development for the Bunny Outfit was stopped and that its almost time for them to start working on it.

So I would not be suprised to one day see Pony can fly, but for now there is no news, because they are not working on it.