Birds do it (1966)

Melvin Byrd, who dreams of being a scientist, is a Cape Kennedy "miniscule molecular particle surveillance monitor" - in short, a janitor. His job is to keep a major rocket project completely dust-free, and this he does with his own hilariously fantastic inventions - including a literal attack on dirt by a "knight on a white horse". In his work, he meets Judy, a chimp involved in a top-secret project, which leads Melvin into the one room strictly off-limits to him. Not until he has entered the project room does Melvin learn that any man entering it will be negatively ionized - making him fly like a bird.