Anoka has the American Wings Air Museum. I haven't been there in a few years but is worth a visit. It's about 25-30 minutes north of the mall.
http://www.americanwings.org/index.htm
In South St. Paul (KSGS) is the Minnesota Wing of the CAF. They have a B-25, Harvard, L-5, BT-13, and PT-22. It's definately worth a visit and is about 15 minutes east of the mall. I heard a rumor that the B-25 might be flying this saturday.
http://www.cafsmw.org/
Also about 5 minutes from the mall is the Minnesota Air Guard Museum. It's closed for the season right now but I work at the base and could probably get you in. Let me know if you're interested.
http://www.mnangmuseum.org/
When are you planning on visiting?