Just Imagine is a 1930 science fiction musical comedy directed by David Butler. The film is probably best known for its art direction and special effects in its portrayal of New York City in an imagined 1980.

Plot:

The film starts with a preamble showing life in 1880, where the people believed themselves the "last word in speed". It switches to 1930, with the streets crowded with automobiles and lined with electric lights and telephone wires. It then switches to 1980, where the tenement houses have morphed into 250-story buildings, connected by suspension bridges and multi-lane elevated roads. J-21 sets his airplane on "hover" mode and converses with the beautiful LN-18. He describes how the marriage tribunal had refused to consider J-21's marital filing and applications, and LN-18 is going to be forced to marry the conceited and mean MT-3. J-21 plans to visit LN-18 that night.
RT-42 tries to cheer him up by taking him to see a horde of surgeons experimentally revive a man from 1930, who was struck by lightning while playing golf, and was killed. The man is taken in hand by RT-42 and J-21, where it is revealed that airplanes have replaced cars, numbers have replaced names, pills have replaced food and liquor, and the only legal babies come from vending machines. That night, LN-18 feigns a headache, and her father and the atrocious MT-3 decide to go to "the show" without her. The second they are gone, RT-42 and J-21 appear and woo B-27 and LN-18 respectively. MT-3 and LN-18's father return quite early, as MT-3 was highly suspicious, and RT-42 and J-21 hide. However, the game is foiled by the moronic Single O, the man from 1930, becoming addicted to pill-highballs, getting drunk, and trying to get some more pill-highballs off of J-21.
J-21 is depressed, but is contacted by Z-4, the scientist. He is told that Z-4 has built a "rocket plane" that can carry three men to Mars. After a farewell party on the "air-liner" (dirigible) Pegasus, which J-21 works at, the rocket blasts off, carrying J-21, RT-42, and Single O, who has stowed away for the synthetic rum. Landing on Mars, they are received by the Queen, Looloo ("I'll say she is!") and the King, Loko ("She is not the Queen---he is!") That night, Looloo and Loko take them to see a "show", which is like a Martian opera, where a horde of trained Martian ourang-outangs dance about. They are suddenly attacked by Booboo and Boko, the evil twins of the King and Queen (everyone on Mars is a twin.) They escape in a highly farcical scene, and return to Earth. As one of the first men on another planet, J-21 is permitted to marry LN-18. The film ends with Single O reunited with his aged son, Axel.