Beyond the Time Barrier

Major Bill Allison flies the experimental X-80 into the year 2024 where a plague has turned most humans into subhuman mutants and the rest are mostly deaf, dumb, and sterile. Once there, the leaders of an underground citadel (not to be confused with the ITTDB Citadel) have plans for him to marry the beautiful telepathic (and possibly non-sterile) Princess Trirene, and thereby re-populate the world. But together with Trirene and a small group of scientists, he devises a plan to return to his own time and prevent the plague from ever occurring.

The flight to the future is explained by scientific gibberish that contains a high concentration of mumbo jumbo, but the gist of it is that the speed of Allison’s plane (around 10,000 mph) added to the rotational speed of the Earth plus the speed of the Earth’s orbit around the sun plus the speed of the Solar System around the center of the galaxy plus maybe another speed or two, managed to bring his total speed close to that of light, which brought him to the future. Apparently, reversing his plane’s path is all that’s needed to return him to the past (ideally with Trirene beside him).

A self-defeating act paradox is set up nicely (if Alison stops the plague, then the citadel in the, future won’t be there to send him back to stop the plague), but the issue is never explicitly discussed and the ending of the film is inconclusive on the matter. Nevertheless, I commend the film for being the first to raise the issue of time travel paradoxes, albeit in the background.