The Real Ghost Army...yes, they did exist.
Updated: Oct 14, 2020
Officially known as the 23rd Headquarters Special Troops, The Ghost Army was a United States Army tactical deception unit deployed during the second world war. This Battalion level unit was given a unique mission within the Allied Army: to impersonate other Allied Army units to deceive the enemy. From a few months after D-Day, when they landed in France, until the end of the war, they staged a massive disinformation campaign, utilizing inflatable tanks, sound trucks, fake radio transmissions. They staged more than 20 battlefield deceptions, often operating very close to the front lines.
The visual deception unit of the Ghost Army was the 603rd Camouflage Engineers. It was equipped with inflatable tanks, cannons, jeeps, trucks, and airplanes that the men would inflate with air compressors, and then camouflage imperfectly so that enemy aerial reconnaissance could see them. They could create fake airfields, troop bivouacs (complete with fake laundry hanging out on clotheslines), motor pools, artillery batteries, and tank formations rapidly. Many of the men in this unit were artists, their unit became an incubator for young artists. Several of these soldier-artists went on to have a major impact on the art world after the war ended.
The 3132 Signal Service Company Special handled sonic deception. Aided by engineers from Bell Labs, a team from the 3132 went to Fort Knox to record sounds of armored and infantry units onto a series of sound effects records. For each deception, sounds could be "mixed" to match the scenario they wanted to portray. This program was recorded on state-of-the-art wire recorders and then played back with powerful amplifiers and speakers mounted on halftracks. The sounds they played could be heard 15 miles away.
"Spoof radio", as it was called, was handled by the Signal Company. Special Operators created phony traffic nets, impersonating the radio operators from real units. Different Morse Code operators each have their own individual style of sending; the Signal Company operators mimicked a departed operator's style.
To complement existing techniques, the unit often employed theatrical effects to supplement the other deceptions. Collectively called "atmosphere", these included simulating actual units deployed elsewhere by the application of their divisional insignias on uniforms and vehicles. The same few covered trucks, with just two troops in the visible seats near the rear to appear to be full of motorized infantry, would then be driven in a loop to look like long convoys. "MPs" (military police) would be deployed at cross roads wearing appropriate divisional insignia and some personnel would dress as divisional generals and staff officers visiting towns where enemy agents or scouts were likely to see them. A few actual tanks and artillery pieces were occasionally assigned to the unit to make the "dummies" in the distance appear more realistic.
Their story was kept secret for more than 40 years after the war, until it was declassified in 1996. Just one year before our Ghost Army was formed.
So why did we choose the name Ghost Army?

Well that is for another time.
'Ghost Army'. Wikipedia. Wikimedia Foundation. September 27,2020. (Accessed 10/12/2020). Available at: https://en.wikipedia.org/wiki/Ghost_Army