Create or turn a mob into something you can fly

I have always felt like there should be a way to fly a mob. It would make use as a fighter for pvp and a way to transport goods. It would be able to go to the end and nether to fight. Maybe it could be some kind of giant bird but i trust Minecraft’s designers would make something super creative. And idk i feel like the name would start with A and have a neutral color palette other than a few bright highlights. But yeah if you take this idea into consideration thanks!