Go down to any of the office supply stores like Office Max and look in the "specialty papers" section for a kind of ink jet printer paper called "Body Tattoo" paper. I know it sounds slightly nuts but read on.

This paper is used to allow you to make kid's fake "tattoos" with your Ink Jet Printer. If you follow the directions in the package you'll end up with a decal with the ink on the sticky side of the thin clear plastic (or vinyl, not sure which) carrier. You simply cut out the graphic you printed, rub it onto the surface of the plane and voila, you have a nice looking decal covered with a very thin plastic sheet. It seems pretty fuel proof but just to be on the safe side I seal the edges of the plastic with thinned clear poly.