Note that the airport supermarket is due to move to a new location, where it supposedly will be larger and nicer. Don't recall exactly when the move was supposed to happen, but I do remember thinking last September, when I was there last, "oh, next time I'll have to look for it in the new location"...

Add: Oh, and the Kaufhof is/used to be right at the Hauptwache, on the Zeil.