German WWII pilots would put bottles of Coca-Cola on the underside of their wings. They weren't weapons, though

While fighting in North Africa, German troops found cases of Coca-Cola that had been left behind by the Allied forces. Due to the extremely hot climate in the region, German fighters were forced to devise a way to cool the beverages prior to consuming them.

In order to cool the drinks, the soldiers would wrap the bottles of Coca-Cola in wet towels and affix them to the underwings of their planes. After landing their planes, the soldiers would have a cool beverage to drink in the hot African sun.

(Source)