I tried to see what happens if you have an elytra riding a horse but when I tried taming a horse nothing would happen so if you right click on it, it would put you on it and he just walks around forever and nothing happens.
I tried summoning an already tamed horse with a command, but then after I put the saddle I can't move him (WASD) and he can't move either. He just moves his head. He can be moved with collision though. Ideas?