In 1917, somewhere in France during World War I, the men of the French Air Force assemble to determine who must rid the skies of the enemy pilot, Baron Sam Von Schpamm. A drawing straws game begins resulting in Porky Pig (addressed as Captain Smedley in this cartoon) selected for the mission. Next day, at dawn, while Porky is suiting up for the flight (whistling Mademoiselle from Armentières), Bugs Bunny knocks him out with a brick and takes his place, because Porky has a family (" . . . a wife and six piglets!").
Meanwhile, somewhere in Germany, Sam (Yosemite Sam) is awarded an Iron Cross for his service. Sam, however, is sick of receiving these and would prefer a well-deserved long furlough. Flying over, Bugs drops him a small bouquet of flowers and a poem. Sam reads and is insulted – Bugs has written "Baron" with a small "B" and claims the Big "B" is in the flowers. When Sam looks at the flowers, a bee flies out and stings his nose. Sam has trouble getting his biplane started but, after confronting the plane and finally taking flight, Sam catches up to Bugs. Bugs pulls up into the clouds. Sam orders him out but doesn't watch where he is going. He crashes into a mountain and starts ranting in German as his plane spirals toward the ground and crashes again.
After hitting the ground, Sam runs back to the airfield and grabs another fighter plane. While he looks for Bugs, Bugs comes up behind and buzz-saws through Sam's plane. In his third attempt, Sam begins shooting at Bugs with a machine gun; Bugs not only dodges but also flies by in all directions and from different angles. Sam's shooting becomes indiscriminate and ends up shearing his own plane to bits, leaving only the undercarriage which becomes a unicycle when he lands. Sam then takes to the skies in a bomber. Having sighted and targeted Bugs, he releases the bombs, but he falls with them and gets caught in the resultant ground explosion.
Sam turns to a small monoplane, which at the push of a lever transforms into a fierce fighting machine quad-plane loaded with engines and machine guns. Sam pulls the switch to full power, but this rips the plane into three parts, causing him to fall to his demise in the ammunition dump. Bugs remarks that he has heard of Hells Angels, but he never thought he would see one. The final scene shows Sam in a devil's suit, playing a harp and floating skyward.
