From wikipedia One of the first uses of dummy tanks during the Second World War was in the North African Campaign. These were foldable, and thus portable. Inflatable dummies consisted of a fabric covering supported by a network of pressurized rubber tubes that formed a kind of "pneumatic skeleton", and they were used in Operation Fortitude prior to Normandy. During this operation, they were used to confuse German intelligence in two ways: first, by making it seem that the Allies had more tanks than they did; and second, to hide and downplay the importance of the location of their real tanks in order to make it seem that the invasion would occur at Pas de Calais rather than at Normandy. However, dummy vehicles played only a small part of the overall deception plan as, at that stage of the war, the Germans were unable to fly reconnaissance planes over England