Sometimes a relatively simple solution is the best one. Such was the case in using barrage balloons, often called “blimps,” in both the First and Second World Wars.
The zeppelin-shaped balloons served as anti-aircraft weapons against enemy airplanes. Metal cables stabilized them, and their shape could be adjusted to withstand harsh winds.
The barrage balloons could reach a height of 14,764 ft/4,500m. Planes traveling at high speed collided with the wires damaging or destroying themselves. On some occasions, explosive charges were strapped to the cables to ensure the destruction of attacking aircraft.
They were first utilized by France, Germany, Italy and the United Kingdom during the First World War. The balloons were often used in cities, to protect important buildings.
By 1918 London had developed a 50-mile net made of barrage balloons, providing protection against the most advanced German bombers at the time. Many reports from the period state that captured German pilots were terrified of the net. The only effective counter-measure were wire cutters installed on the wings of an aircraft. However, such measures would not be developed before the outbreak of WWII.
In 1938, the British established the Royal Air Force Balloon Command which was responsible for protecting cities, industrial facilities, harbors, and other places of strategic importance. The development of dive bombing tactics by the Germans at Guernica during the Spanish Civil War, and their devastating effect had served as a warning to the British Government.