So, hot air balloons were invented in 1783. They were used in many wars, including the French revolutionary wars, second Italian war of independence, Franco-Prussian war, and more. When Austria began seizing Venice in 1849, they put bombs on air balloons and dropped them. Almost like a bomber plane! Rush to the American civil war, we have Grenades, why weren’t those dropped off the balloons? Prototype rocket launchers were used by both sides, why weren’t those put on balloons? Both sides had a sniper rifle being used, why don’t you put a sniper on the balloon? Or just normal rifleman, hell but a Gatling gun on one, or a light cannon perhaps. Or at least, why didn’t they use them as bombers like in 1849?
This is really a question of technology, not history.
A balloon, especially a XIX century hot air design, is an incredibly unpredictable platform. You have no control over its speed or direction of travel, and a very limited control over changes in elevation. Trying to accurately hit anything with a mid-XIX century rifle from a free floating balloon is a pipe dream.
A Gatling gun or a rocket would be even less practical and outright dangerous. A Gatling is a very heavy beast and the last thing you want is to mount it on an unstable air balloon. A rocket's stream of burning gases is going to set everything behind it on fire.
This leaves bombs. The unmanned bombs used by Austrians in Venice relied on constant, steady, predictable winds blowing from the sea inland with the same intensity and same direction. Even then, this was more of a novelty / morale weapon than anything else. No match for artillery.
In short, this would be just too impractical, ineffective, and overall just a waste of resources.
Hey there,
Just to let you know, your question is fine, and we're letting it stand. However, you should be aware that questions framed as 'Why didn't X do Y' relatively often don't get an answer that meets our standards (in our experience as moderators). There are a few reasons for this. Firstly, it often can be difficult to prove the counterfactual: historians know much more about what happened than what might have happened. Secondly, 'why didn't X do Y' questions are sometimes phrased in an ahistorical way. It's worth remembering that people in the past couldn't see into the future, and they generally didn't have all the information we now have about their situations; things that look obvious now didn't necessarily look that way at the time.
If you end up not getting a response after a day or two, consider asking a new question focusing instead on why what happened did happen (rather than why what didn't happen didn't happen) - this kind of question is more likely to get a response in our experience. Hope this helps!