Pre-Flight lets you define your own custom waypoints. Unlike many other planning tools, you do not have to enter each or your coordinates, you simply use a map and drag a pin into position. Mighty useful when flying VFR! Its much easier to simply put a pin on that intersection of railway and road using a digital map rather then trying to read the coordinates from an ICAO chart using a ruler and protractor. When entering a new waypoint it is often useful to see how this waypoint is positioned with regards to the existing route. Often you simply want to enter waypoints on clearly recognizable landmarks to split a long leg into less sizable chunks. For this reason the current route is displayed as a line in the waypoint editor.