Repairing is possible as most look like problems with the paint. You need to find out what type of paint it is. Buy a bottle of yellow butyrate dope, some yellow Coverrite paint, and a can of Lusterkote clean off the plane with some denatured alcohol, and paint a test patch's on the bottom. If both Lusterkote and the dope work with no problems then the plane is likely painted with butyrate dope, if only the Lustercote then it was painted with Lustercote or automotive acrylic lacquer, if the Coverrite paint is the only one that works then the plane was covered in Coverrite or painted with a polyester paint. Once you know what it is you can buy material and paint to patch it.