The only things model related I ever saw on Beaver was an episode where he spent his uncle's birthday money on a tether car, A Cox Mercedes racer I think, another one dealing with kites, and one where Beaver has a stick and tissue model on a building board in his room.
The show "Hazel" had at least one episode where the boy in the series was flying control line models. Lassie had an episode where Timmy was lusting after a plastic RTF model in the toy store window, and after Lassie saved him from the well again, they showed him flying it in the family pasture.
The best was probably the My Three Sons episode that was mentioned. It's on YouTube in three segments and was sponsored by Wen-Mac. Search here for the previous thread that had the link.
Type at you later,
Dan McEntee