Continuity mistake: During the middle of the film, a butler comes in and out of the Dictator's office several times repeatedly. The door is open and shows the corridor outside the office, casting the shadow of a window off-screen. The shadow changes from small to big bewteen shots.
Other mistake: In the windmill scene, the windmill reverses directions twice to signal the airplane. However when Joel McRae enters the windmill and we see the machinery it is obvious that there is no mechanism to reverse the windmill against the wind.