Flight To Mars (1951)

A space ship carrying four scientists and a wisecracking news reporter lands on the planet Mars and discovers signs of an underground civilization. They are greeted by its apparently friendly population and made to feel welcome while they repair their ship for the voyage home. Dr. Jim Barker, the expedition's leader, falls in love with the beautiful Alita, daughter of Tillamar, an influential member of the Martian governing council and learns that Ikron, the council's militant leader, plans on using the repaired ship to invade the Earth. Natural resources on Mars are dwindling, and unless the Martians can recolonize on Earth, their civilization is doomed. Barker hides his knowledge of the council's plans tries to complete the repair work ahead of schedule, so their party, along with Alia, can return to Earth without betraying their plans to Ikron.