 In the beginning of the film in the Sonora Desert, inside one of the  WWII vintage aircraft they pull a calendar that looks vintage from  1945. Across the grid of the days of a full month on the calendar is  plainly seen a light blue logo from the defunct Security National  Bank (which did not exist in 1945). In the fall of 1972, Security  National Bank issued a 1973 calendar that corresponded exactly month  by month, day by day, to the 1945 calendar for fun. Thus this unique  idea was the freebie promotional give away to the banks customers.  The prop crew for CE3K probably could not locate an authentic 1945  calendar so instead inserted the fake vintage calendar which was not  hard to find.