It’s About Time was produced by the immortal Sherwood Schwartz, creator of The Brady Bunch and Gilligan’s Island (Gilligan was then in its third year earning solid ratings for CBS).
It’s About Time ran only one season on CBS, from September 11, 1966 until August 27, 1967; the sitcom starred Jack Mullaney and Frank Aletter as two 1960’s astronauts who break the time barrier and end up in prehistoric times.
Oh my goodness! My parent’s must have watched every episode. I know the theme and I was only four.