"Were terrorists planning to spread anthrax from a crop duster? That would be very difficult to do effectively, because anthrax droplets need to be small enough to float, and crop dusters are designed to spray droplets that don't."
Assumptions: The terrorists were informed enough to know that the crop dusters would not do this "effectively." Terrs would not do it because it would be "difficult." Terrs would not have knowledge to make it more "effective."
More frightening still... How about a weaponized versiom of Bubonic plague?????? Remember the Japs in WWII was studying Weaponizing Bubonic Plague in their INFAMOUS Unit 731A believe....