Operation Fortitude was a crucial, bold, almost insane, factor in the success of D-Day in 1944. It was a hugely elaborate hoax, to make the enemy believe that the Allies’ continental invasion would happen across the straits of Calais (Fortitude South) and from Scotland into Norway (Fortitude North).
Physical deception was the element of the deception on which least emphasis was placed. In older versions of the plan [of Operation Fortitude] this had not been so. The movement of real troops and the building of fake camps had been envisaged on a sizeable scale, along with widespread displays of dummy tanks and aeroplanes. [Major David] Strangeways had stripped his plan of most of thee elements. Partly this reflected a lack of resources, for if the work had to be compromised, or if the preparation necessary was too elaborate, the deception risked being revealed.
An example of this had occurred earlier in the war in Holland when the Germans built a full-scale replica of an airfield out of wood. It proved so painstaking to put together that Allied intelligence was able to observe its construction and note its completion. The next day a British aircraft flew overhead and dropped a single wooden bomb onto it. But Strangeways’ primary reason for eschewing physical deception was that the Luftwaffe was simply not carrying out enough reconnaissance to make the effort worthwhile. (Operation Fortitude, Joshua Levine, 2011, p232)
I love this. Just imagining the bods who constructed the wooden bomb fills me with glee.