he may have a bankai. he never denied having one, just that what he used was his shikai.
If you are talking about Aya... I gotta stand by my first observation. No way does he have Bankai. Ichigo couldn't attain it until he let go his childish ways. Same with Renji. I seriously doubt Bankai is going to manifest to someone with Aya's shallow mentality.
Thing is a lot of people may see Aya's Shikai as weak or boring. But it's got the most potential to destroy as any I have ever seen. And thats just the initial release. Used right... it has the actual potential in it's initial release to beat a Bankai if you really think of what it does. Thats a little scary actually.
then i must object. my counter point is that bankai has nothing to do with maturity, but desire and skill to develop into a better fighter.
btw, before I even go further, I just want to say that I was saying that he MAY have bankai, but he doesnt say in the episode that he does or doesnt, just that what he used was his shakai
Cool a debate!

Actually bankai does have a lot to do with maturity and where the desire to fight stems from. It's why Zaraki can't use it. He has not found the confidence in his spiritual partner (what I perceive bankai to be) to work in a mature partnership with it. Ichigo managed to realize that need and Zangetsu answered. I think we can all agree that (esp after his fight with Ichi) Zaraki has a VERY strong desire to be stronger and fight. Yet still he can not use Bankai.
Bankai has a strong spiritual element to it. Aya doesn't have it. You are right... they don't say he "doesn't" have it... but it most definitely does not follow that he does If he ends up having it I think that will be the biggest plot twist in the last 60 chaps at least.
Now Hisagi may have it.. or attain it very soon.