i'm in your conscience
You can rebattle the trainers in Pyrite Town. :) There's also the Pre-Gym if you haven't done that, in Phenac City. Also, merging this with the Q&A thread since it's question-y. Then we also won't have to deal with the inaccurate title, lol.
Edit: btw, Altaria ia an amazing Pokemon that you should keep on your permanent team! I'm really biased though lol