The Flight that Disappeared (1961) starring Craig Hill, Paula Raymond, Dayton Lummis
Some people have described The Flight that Disappeared as being like an episode of the Twilight Zone. And that’s somewhat accurate, although it’s more than that. For example, unlike the relatively short Twilight Zone episodes, The Flight that Disappeared actually takes time to flesh out the secondary characters, so that the audience can care about them. For example, on board the propeller-driven airplane, this is the captain’s final flight. He’s going to be flying jets in the future. In the same way, his second in command is going to be promoted, and marry one of the stewardesses. And these are the secondary characters …
The primary characters
At the same time, two other passengers — Tom Endicott (Craig Hill) and Marcia Paxton (Paula Raymond) are seatmates and introduce themselves. The flight goes on, without incident, until it begins gaining altitude for no reason. And the pilots cannot level it off, or reduce the altitude.
Soon, it becomes obvious the Endicott, Paxton, and Morris are connected. Dr. Morris and Miss Paxton have developed — theoretically — a new type of nuclear weapon that can literally destroy an entire nation in one blow. And Tom Endicott is a missile engineer, who is developing a missile powerful enough to deliver it anywhere on Earth. And the plane keeps climbing, and the oxygen is getting thinner …
The second half of the movie deals with these three being put on trial (not by aliens, as some places report) — but I won’t spoil it. It’s a good movie, that leads to a decision for the three, that impacts the world — and invites the audience to think about consequences.