According to Don Knotts's autobiography, the idea of the film originated during the writing of The Ghost and Mr. Chicken (1966). Knotts and screenwriter James Fritzell were in a tall building writing the script, but Fritzell's partner, Everett Greenbaum, wouldn't join them because of his fear of heights. Knotts and Fritzell then began joking about the worst job to have if one was scared of heights. Being an astronaut was the top choice.
This film premiered 25 January 1967, just two days before the Apollo 1 Fire, which took the lives of 3 astronauts and raised questions with Universal Studios executives about the appropriateness of releasing a space-themed comedy film so soon after the tragedy. It was released anyway and the tragedy may have affected the box office results in the following weeks, since this picture was not nearly as successful as Knotts' two previous features, Der erstaunliche Mr. Limpet (1964) and The Ghost and Mr. Chicken (1966). Universal had doubled the budget of this movie to $1M on the success of the latter film.
Partially filmed at Johnson Space Center in Houston.
The house the Flemings live in is the same set in which James Stewart and his aunts lived, in Mein Freund Harvey (1950), which also co-starred Jesse White.