Editing: I believe that Casablanca uses Continuity editing as a way to create a steady flow within the film.

An example of this is the plane scene at the beginning of the film. It uses a Mid shot to make the plane the focal point

Below is a medium shot of the people in the Café. It is shown like this to immerse you in the world from the view of someone in the café.

This is a medium shot of people viewing the plane landing. The shot tracks to show all the reactions

This is a close up shot of IIsla Lund to show her reaction and emotion

Below is a similar close up of Rick to show his emotions he’s feeling.