Welcome to Matt's Army Humor!
A military cargo plane, flying over a populated area, suddenly loses power and starts to nose down. The pilot tries to pull up, but with all their cargo, the plane is too heavy. So he yells to the soldiers in back to throw things out to make the plane lighter. They throw out a pistol. "Throw out more!" shouts the pilot. So they throw out a rifle. "More!" he cries again. They heave out a missile, and the pilot regains control.
He pulls out of the dive and lands safely at an airport. They get into a jeep and drive off. Pretty soon they meet a boy on the side of the road who's crying. They ask him why he's crying and he says "A pistol hit me on the head!" They drive more and meet another boy who's crying even harder. Again they ask why and the boy says, "A rifle hit me on the head!" They apologize and keep driving. They meet a boy on the sidewalk who's laughing hysterically. They ask him, "Kid, what's so funny?" The boy replies, "I farted and blew up my school!"