The Last Roundup 81 years old

Gandy Goose is helping test artillery by putting an apple on his head (to a swinging version of the William Tell Overture). The first shell is spot on. He backs up against a tree, and this shell comes in low, sending Gandy through a whole line of trees. The "dud" explodes, and sends both Gandy and his sergeant rocketing into the air. They land in a haystack; when all the insects greet them with "Heil", they figure out they're in Germany, conveniently near a piglike Hitler and his monkey, Mussolini.