Near the beginning of the film, a poster, headed "Wanted for treason" is seen on a wall. It includes head-on and sideways pictures, like police "mug shots". A similar poster was published in Dallas with picture of President Kennedy before his assassination.
On arrival at the station in Dallas, the President's wife is given some red roses. The same thing happened to Jackie Kennedy on arrival at Love Field for President Kennedy's visit to Dallas. They should have been yellow, to commemorate "The Yellow Rose of Texas", but all the yellow roses had already been placed at the Trade Mart, where JFK was due to speak, and only red ones were available.
Van Johnson's voice is dubbed by another actor in the English language version.