Bought a old plane that has covering that looks like silk but is more like a paper. This stuff is hard. The plane is very old and I would like to recover it. Any idea how to get this stuff off?

Sounds like it's covered with silkspan. It's sort of like the "paper" a teabag is made of. You should be able to sand it right off, and use some M.E.K. acetone, or other solvent to remove any residue from the old dope.