In my experience, it can be used in two ways.
1) It establishes the location that the next scene will take place in. For example, I used a shot tilting up the outside of a skyscraper in this video. The viewer then gets the sense that the next shot (of a board room) takes place inside that skyscraper.
2) Flyovers between scenes can also evoke a sense that time is passing, though the location of the following scene is the same as the previous scene. Movies also sometimes use a shot of an inanimate object in the room, such as a sculpture or piece of art, for a few seconds, in order to show passage of time. It puts the characters and action in the background and gives the viewers a visual break. The technique is equivalent to a novel ending one chapter and starting another one, or displaying extra white space between paragraphs.