How do the flyover zones keep the zombies in the Urban areas when all hell happens and the cities collapse?
No need to worry... Those City zombies will stay in their comfort zone and the outside world will remain safe...heh.
They will then collapse upon themselves without support of the outside farmers (no food). As usual, the outsiders will always prevail - God, guns, food, and beliefs...
Okay, a silly question does require a silly answer you know...