The Kievan People wrote:Aerodynamic dispersal of chemical and biological weapons allows for precise control of particle size, eliminates flashing and allows for precise control of concentration.
Spraying a cloud of BC agent from an aircraft, cruise missile or drone downwind from the target is perhaps the most effective form of delivery. Assuming the wind is blowing at a good speed, it will roll over them like an advancing wall of doom. Of course if the wind is absent, intermittent or exceedingly strong this method is much less effective.
Why not just fly a cruise missile over them and spray directly overhead? (Assuming no wind)