I flew to a French show once where they had the crowd line aced. If viewed from above you had the crowd line, display aircraft parking, a small earth berm, the display line and then the runway. The dl seemed to be variable with jets at 100 meters or so from the crowd and Pistons a little closer, enough to get a good view and enjoy the sound! With the parking in front of the crowd there was always something going on for the punters to watch.