The V1s were unmanned jet aircraft analogous to cruise missiles. They were launched towards England from Northern France and the Low Countries starting in 1944. The V1s were extremely simple devices that carried 850kg of explosive a distance of up to 250km. The missiles were launched in the general direction of London with a timer set for the expected length of time to reach the target. When the timer ran out, the engine stopped and the missile crashed, setting off the explosive. I remember people telling me about living in London that summer. Everyone listened. The V1 pulse jet engine had a very loud and distinctive put-put sound. As long as you could hear the engine, you were safe. If the engine stopped, however, you had better find cover quick.
Various methods of dealing with the V1s were developed, but none were completely satisfactory. The V1s flew above the range of light aircraft guns and below the range of heavy guns. Normal fighters couldn't catch them, and except risking death by blowing up the warhead, had trouble doing significant damage to the simple mechanisms. Eventually, groups of tuned up fighters were deployed with tactics that allowed shooting from far away. New anti-aircraft batteries with radar guidance and proximity fused projectiles were created. By late 1944, most V1s were destroyed before they could hit anything important. Allied advances on the Continent also pushed back the launch sites out of range of London. The Germans switched to targeting the port of Antwerp and started air-launching over the North Sea to get at London. Between June 1944 and March 1945, the Germans launched approximately 10,000 against Britain and a similar number against Belgium.
One of the most effective counter-measures depended on the previously referenced intelligence war . Because the Germans couldn't get any aerial reconnaissance over England in 1944, they depended on their agents to tell them where the bombs were landing. Of course the English had turned all the German agents, who dutifully reported that the V1s were landing north of London. Based on this information, the missiles' timers were reduced, causing most of them to drop South of the city.
During the early days, in June 1944, only a few British and American fighters could catch the 390mph V1s. As noted, to get close enough to do damage was also close enough to get killed if the warhead exploded. Pilots developed the remarkable technique of flying up beside the V1 and putting their wingtip under that of the V1 and tipping the missile. This would cause it to lose control and crash. An extremely dangerous maneuver done only a few times and amazingly caught on film. The photo below shows a Spitfire XIV tipping a V1 over southern England in June or July 1944.
