Details man, details... What kind of plane? Fully sheeted? Partially open structure? 40 sized? Giant scale?
If it's partially open structure, I'd go with something like Solartex sold by Balsa USA. It's available by other names like Colortex, Worldtex, etc. but it's all the same. It takes paint beautifully.
If it's fully sheeted like a Top Flite warbird, go with fiberglass cloth.