You can go to your local general aviation airport and pick up a copy of the approach plates, standard instrument arrivals (STARs), and standard instrument departures (DPs) to get the exact routing of aircraft into a given airport. The short answer to you question is that most aircraft follow a standard route that is usually very precise, especially on arrival. The final approach fix, beyond which no vectoring occurs, is usually no closer then 5nm to the airport. At busy international airports there is usually very little vectoring of inbound commercial air traffic anyway, the standard arrivals keep the flow organized and efficient. There are usually several different approaches into a given airport, however, and aircraft landing on parallel runways will fly similar headings with offset ground tracks.