The frame around the windshield of Dr. Smith's car keeps changing throughout the film. The windshield wipers are missing, sometimes the holes for them are visible, and sometimes the wiper arm pins are present in the windshield frame.
A shadow of the boom microphone is visible on top of the trailer after it pulls out of Omaha's city limits about one hour into the film.
When Larry first finds Diane in his trailer and begins questioning her, she tells him that she has an uncle in San Francisco, but Larry has not yet told her that San Francisco is his destination.