"When and where and by whom was the first aerial bombardment."
Fair enough, the first air unit was just that one balloon at Fleurus. Napoleon didn't go much on 'loons, he believed their slow deployment hindered his army rather than helped it, so he ordered it to be disbanded.
My first answer referred to bombardment by
manned aircraft. As for
unmanned aircraft:
The first aerial bombardment was undertaken by the Austrians against the Venetians in March 1849, when Oberleutnant Franz Uchatius designed and launched several score paper balloons, each carrying a 30lb (13.5kg) bomb. The balloons were intended to drift with the wind across the city and release their bombs in response to a time fuse.
Source: Page 2 of
The Guinness History of Air Warfare by D. Brown, C. Shores and K. Macksey; 1976, Guinness Superlatives Ltd., Enfield, SBN 900424 61 3. Which is where I suspect you got the Fleurus balloon gen, Angus?
A lighter-than-air flying machine such as a balloon or airship is still properly described as an aircraft; so is the heavier-than-air aeroplane (or airplane, if you prefer), which derives its name from the plane surfaces from which it gains lift. So a bombardment from a balloon is valid in the context of this thread.
