I can only imagine what 66 years of age does to rubber (or "rubber-type materials", as purported to be used in the Inflatoplane).it was in pretty sad shape.
Fill it with helium
what would the engine sound like?You will know it has a leak when the pilot sounds like Mickey Mouse...
There was one on display at an exhibition at IAD (Dulles) in 1972, "Transpo 72" I think the event was called. I was just a teenager, but it seemed an unlikely/impractical endeavor even then.