During the later half of the sceond world war, Germany experimented with a wide variety of odd weapons, many using natural elements as a weapon. In 1944, Albert Speer launched plans to design several different efficient weapons to stop the Allies' massive advance, one was the Air Gun. The idea was to fuel the gun with hydrogen and oxygen, which would cause a trumendous explosion, and out would come a plud of air. The point was to concentrate this "invisible plud of air" at a low-flying airplane, and the power from the blast would simply tear the plane apart.
Examples were produced and used during WW2, and I think it would just be an awesome addition to the game!