According to an article in the now discontinued bus magazine "Bus World", in 1976 the film's actual big bus itself made a real-life trip in California from Los Angeles to San Diego to promote the picture.
On the news van that appears near the beginning of the film, the call letters are WZAZ. These call letters also appear in many comedies from what's known as the "ZAZ" team - Jerry Zucker, Jim Abrahams, David Zucker - though they had nothing to do with this film. See Airplane! (1980).
The film's opening prologue reads: "There have been Movies about Big Earthquakes . . . There have been Movies about Big Boats sinking . . . Movies about Big Buildings burning . . . Movies about Big German Balloons busting . . . And now a Movie about . . . " .