I was thinking either a Hippogriff or Pegasus. I would buy the young (3k gp either way) and train it for Combat Riding myself, using the Riding Bracers and a mwk tool to get a total of +15 on my Handle Animal check so I could take 10.
I'd then swap the Sphinx Claws for Riding Bracers in everyday use.
The only difficult part would be if you said a Pegasus started as unfriendly, in which case I couldn't make it friendly (my max wild empathy for a magical beast is +2). If it started as indifferent it would still be difficult.
...and lol, no fleshraker. I need something that can fly
This is cheaper than a magic item, and it can fight.
EDIT: I just realized I asked about animals, not magical beasts... hopefully this will be ok.
EDIT2: And would I be able to pick its feats? I'd prefer a Peg, and if changing my alignment to good would help I can easily do that.