One of the commenters at SciFi's BSG forum was an F-16 pilot who'd just returned from Iraq and whose rotation had him training new pilots. I talked up the idea of using a zombie attack as a planning exercise and he used it in class. Given the close proximity of civilians and zombies, strafing runs with the 20mm cannon was crucial.
I recently read an interesting article on how the zombie genre was born from terrifying rabies outbreaks that once afflicted major cities like Paris, where you could be walking down an alley, get attacked by a rabid animal, and get turned into a mindless, vicious monster. It made sense.