What should I use that I can cover some mdf/wood with? I am making a biplane and want it to sit off the ground, so I'm cutting a base. Should I just cover it with foil or is there some kind of paint or something that I should apply to it that would be foodsafe? Any ideas or suggestions?? Also, I've only used fondant, would gum paste dry hard enough to make wings with, or do I need to make those with wood also?

The wood can be covered in fondant. I don't like to paint the wood for fear of toxins in the paint leaching into the cake. Possibly you could use food coloring and stain the wood? The fondant for the wings would work but they do take a while to dry. If you have any tylose you can add that to the fondant. They will dry firmer, faster and be more stable.