Sideral Cruises (1942)

In 1942, Robert and Françoise Monier make a hot air balloon to fly to the stratosphere. Before leaving, the husband has an accident. His wife carries out the experiment with the laboratory assistant. The balloon drags them along towards space; after a visit to Venus where they meet a couple fluent in French, they land on the good old Earth but, (theory of relativity) they have aged fifteen days whereas on their native planet, twenty-five years have passed.