Seventy-five years ago, American P-38 fighter-bombers embarked on an unusual sortie dubbed “Operation Cornflakes”. The twin-engine fighters were tasked with dropping an unconventional payload, as detailed by Tyler Bamford of the National World War II Museum.

On January 5, 1945, after an initial wave of P-38 strafed a German mail train bound for Linz, Austria, a second wave of P-38s dropped eight bags of mail over the damaged freight cars.

While dropping Allied propaganda into German towns was nothing new, these pamphlets were unique in that they were addressed to actual German citizens and businesses. Designed to bring subversive propaganda to the German breakfast table, writes Patrick K. O’Donnell in Operatives, Spies, and Saboteurs, Operation Cornflakes was intended to further demoralize the German population.

The hope was that the dropped mail would mix in with the real mail from the destroyed train—with the added twist of the proverbial knife that the propaganda would then be hand-delivered by the German postal service.

The Office of Strategic Services (OSS), in charge of America’s psychological warfare efforts, reasoned that German citizens were more likely to read the Allied pamphlets in the privacy of their own homes rather than in full view of their neighbors—and potentially the ever-watching Gestapo.

The OSS was meticulous in its planning—with agents combing through POW camps for German prisoners who had worked as mail clerks to glean an understanding of the inner workings of Nazi Germany’s postal service. Furthermore, down to the very material, the OSS created identical Nazi mail pouches that were indistinguishable from real German mail bags. They strayed only slightly when creating the postage stamp—depicting Hitler with his jaw eaten away and replacing the words Deutsches Reich (German Empire) with Futsches Reich (Ruined Empire).

However, in the final months of the war, the OSS hit a snag. The German government had restricted mail services to only that of official business matters. This shift from domestic mail required the OSS to scour “prewar German directories and wartime newspapers for addresses,” writes the National World War II Museum. “The OSS mail also contained a plausible mixture of hand addressed and typed envelopes, as well as newspapers depicting the German high command as divided and demoralized.”

According to O’Donnell, the 14th Fighter Squadron of the 15th Air Force participated in 20 missions during Operation Cornflakes—dropping 320 mail bags containing 96,000 forged letters over southern Germany and Austria between the months of February and April of 1945.

After the war it was found that the Allied propaganda did reach the homes of some Germans. However, the overarching impact of the operation on German morale was not exactly quantifiable. And, ironically, due to the increased tempo of the Allied bombing campaign that spring, many of the intended targets had become refugees. With no place for the mail to be delivered, much of it was eventually destroyed by the German government, rendering “Cornflakes” kaput.