Just for fun and giggles check with a body shop. Ask them to clear coat your plane when they are doing another job. that way they will use "leftovers" in the gun. It doesn't take much do a medium size plane. Also ask to "go lite" on the paint and explain that weight is the enemy especially at the rear of the plane.

If you have a shop you've been to for your car, they might be more friendly towards you.

Ken