Oswald's 'plan to hijack a plane to gain entry into Cuba' is just one of Marina's crazy stories. He never had such a plan. He didn't need to. He could have travelled to Cuba by peaceful means, the only limitation imposed by his financial means. The notion that Lee wanted to to Cuba to train the Cuban army (single-handedly?) is ludicrous. The story falls in the same category as his alleged intent to assassinate Richard Nixon: it never happened.