My son had an Air Force themed birthday party. I tried my hand at an airplane cake.
One cake mix
Bake a 9x13 cake as directed. Cool. Cut into 2 rectangles - 5x13 & 4x13 The 5x13 will be the body. Trim the top edges to form the nose. Use the excess to form cockpit. Cut the other rectangle into two more - 4x9 & 4x4 Then cut these two diagonally to form the 4 wings. Cut the graham cracker diagonally to form the upright wings. (Mine cracked a little so I used a toothpick to hold it up)
Frost the cake with your choice of colors. I found it easier to frost with thinner frosting. Pipe the outline to help form the plane shape. Use any candy/decorations you desire. I used Cocoa Krispies cereal straws to form the "guns" and after-burners. I also inserted candles into the edge of the wings to look like missles. Just be careful when lighting.