Balloons were actually used quite a lot military, having their heyday in WWI https://en.wikipedia.org/wiki/History_of_military_ballooning https://en.wikipedia.

Balloons were actually used quite a lot military, having their heyday in WWI https://en.wikipedia.org/wiki/History_of_military_ballooning https://en.wikipedia.org/wiki/History_of_military_ballooning Looking at the other direction (balloons shot down), there were indeed quite a number of them over the WWI battlefields! https://en.wikipedia.org/wiki/Balloon_buster https://en.wikipedia.org/wiki/Balloon_buster