The Cargo Version of a B-24 could work. It could just be an AI flying in circles and you cant shoot it down. It will only do that for it's own country or until it's orginal base is taken.
Taking the base might be difficult. Unless instead of destroying the town, you just paint it a different color...
Hey.. then we could change the chess pieces to RGB colors. ( add a 4th country and go with CMYK for all the graphics designer professionals )
Hmmm...