 Sometimes several airports in a locality share a single STAR; in such circumstances, aircraft follow the same arrival route until the final waypoint, diverging thereafter for their chosen destination.Although the route segment of the filed flight plan does not usually change during the flight itself, the STAR to be flown might well vary according to the weather, the runway or approach in use, or the need to safely separate air traffic, among other factors.Thus a filed flight plan typically ends some distance from touchdown, where a STAR begins, and that is usually assigned and communicated to the pilot during the flight planned portion of the flight.