Each player picks an airplane. Each player then receives a number of M&Ms (or similar small candy) equal to the damage points of the plane selected.
When a player inflicts damage on another player's plane, the firing player takes a number of M&Ms equal to the damage inflicted. (Yes, this does remove the "secret damage" function, but this isn't meant to be taken seriously. )
The winner is the player with the most M&Ms at game's end -- in more ways than one.