I didnt use any water applying the decals. You might try spraying windex on the plane where the decal goes, then peel and place. This allows you to align and center the decal. The windex will evaporate naturally, then the adhesive goes ahead and cures. For added protection from fuel and other elements of flying, spray with monocaot clear coat paint over the decal. Be careful, it gives the surface a nice luster and one can get carried away. Kinda looks like the clear coat on your new car. Its even safe enough for your covering such as monocoat, ultracoat and 21st century.

later,
chris