Airplanes are cool. Fighters are sexy, bombers are strong, transports are reliable. Everybody seems to like airplanes. Balloons are seldom considered by most people, possibly because there are so simple; but they have had significant military use, and that use isn't finished yet.
Any military equipment serves to extend the individual's body and senses. Shortly after its invention and successful demonstration by the Montgolfier brothers in June 1783, the French were extending their eyes with hot air balloons. The French army used balloons as elevated observation posts during the sieges and campaigns of 1793-1795. Two men crewed the balloon and used flags and weighted messages to communicate with the ground. http://www.deadmedia.org/notes/2/026.html
Their position gave them a field of observation of over twenty miles radius, and allowed a commander to have a much clearer picture of the battlefield and of enemy troops arriving in the vicinity of the battle. With the excellent observation provided by balloons, an army could maneuver to strike its enemy in the rear or flank with much more efficiency than if both sides are just stumbling around, hoping to trip over each other. Napoleon supposedly went up in a hot air balloon on at least one occasion to observe enemy movements. He had initially been opposed to this new technology; and failed to use it during his Mid East campaign, at the siege of Acre. Later, he came to see the value of aerial observation, and used balloons in a number of campaigns.
How much of the French success can be attributed to the balloon Corps isn't known, but how much better will one army do than the other, when he can see and his opponent can't?
The next significant use of balloons occurred during the American Civil War. http://www.thehistorynet.com/CivilWarTim... Both sides used them for observation of enemy movements; but neither side really embraced the concept. President Lincoln created the Balloon Corps after demonstrations at the White House by, and the War Department contracted civilians to operate it. The Corps did not limit itself to passive observation, but also became involved in spotting artillery fire, making this the first time in history that artillery had operated as 'indirect fire'; or shooting without the gunners being able to see their own targets.
