List of World War I aviators who shot down four observation balloons

The crucial role of observation balloons
Balloon busters were military pilots known for destroying enemy observation balloons. These pilots were noted for their near-suicidal fearlessness.

An observation balloon was both a vulnerable and a valuable target: the balloon was moored in a stationary position and was lifted by flammable hydrogen gas, whose use was necessitated by the scarcity of helium reserves among European powers. The observer, suspended in the wicker basket beneath, typically had a wireless transmitter, binoculars and/or a long-range camera. His job was to observe actions on the front-line and behind it, to spot enemy troop movements or unusual activity of any sort, and to call down artillery fire onto any worthwhile targets. Balloon Observers were consequently targets of great importance to both sides, especially before any sort of infantry action or offensive, so individual pilots, flights or whole squadrons were frequently ordered to attack balloons, either in an attempt to destroy them or at least disrupt their observation activities.

Due to their importance balloons were usually given heavy defenses in the form of anti-aircraft artillery and standing fighter patrols stationed overhead. Other defenses included surrounding the main balloon with barrage balloons; stringing cables in the air in the vicinity of the balloons; putting machine guns in gondolas for observers to use; and flying balloons booby-trapped with explosives that could be remotely detonated from the ground. These measures made balloons valuable but very dangerous targets to approach.

Although balloons were occasionally shot down by small-arms fire, generally it was difficult to shoot down a balloon with solid bullets, particularly at the distances and altitude involved. Ordinary bullets would pass relatively harmlessly through the hydrogen gas bag, merely holing the fabric. Hits on the wicker car could however kill the observer.

One method employed was the solid-fuelled Le Prieur rocket invented by Frenchman Lt. Yves Le Prieur and first used in April 1916. Rockets were attached to each outboard strut of a biplane fighter aircraft and fired through steel tubes using an electrical trigger. The rockets' inaccuracy was such that pilots had to fly very close to their target before firing.

It was not until special Pomeroy incendiary bullets and the Buckingham flat-nosed .45 calibre explosive bullet became available on the Western Front in 1917 that any consistent degree of success was achieved. Le Prieur rockets were withdrawn from service in 1918 once incendiary bullets had become available.

Aviators with victories over four observation balloons
The following list is accumulative and incomplete because it is a work in progress. It is compiled as biographies of flying aces are written, and still lacks some balloon busters. Citations are requested for all additions, preferably to texts in Reference section.

Please feel free to Expand list by adding to it. Citations are requested for all additions, preferably to texts in Reference section.