The included .PLN files are the Msoft flight plans, giving basic heading, distance, minimum altitude, fuel, and time estimates, with enroute nav aids, if available. They also provide the maps of the route needed for sextant lines of position to be drawn on.  (Printed out before take off, of course, to avoid the game providing you with your exact position).

The .PLN files go in the "Flight Simulator Files" folder for FS2004, or in the "flights\myflts" folder for FS2002.  In FS2004, the "Flight Simulator Files" folder is usually found in the "My Documents" folder.

The .PLN files may then be called up from the kneepad, or by selecting, from the main window, 'Flights' then 'flight planner' pull down menus, and click on 'load'.