Tite Kobo said that in the next arc Aizen will appear again! aizenplz And many other things...So yes, Aizen is in this moment is jail. It is 100% sure If you want the side where is the interview tell me.
I doubt that its part of his plan, but he'll have a plan for escaping for sure... maybe he wasn't prepared for Ichigo and Urahara defeating him, but there are the zero guard and the spirit king himself who he would have had to defeat when he wants to be spirit king, so he has to have a plan for the case of failure.
I'm actually wondering if he's going to be slightly unvillainized and Ichigo will break him out.
(This is all spawning from the scene where Ichigo told Urahara that he wondered if Aizen himself wished in some small part to lose his powers, which was why the hokyouku finally turned away from him. Then Urahara has this funny look on his face - which manga characters usually do when they know something uber-special that we're not allowed to know about yet. Therefore it makes me think there's some overarching plot even larger. It will either set Aizen up as the supervillain or Ichigo will break him out because it turns out the King is really the evil one, or some random twist like that. That's my very vague theory anyhow.)