…an online flight planning and mapping tool located at http://il2missionplanner.com/
Very useful to have on a second screen or tablet instead of it taking up all your screen while flying. You can also plan your routes and share them beforehand.
If you fly with a second PC or a tablet beside you then you can indeed mark your current position and get a new heading to the target or home. You make a flight plan by putting waypoints on the map and it then gives you bearings & times. If you find yourself off course after a fight or avoiding enemy patrols you can just drag a waypoint to your current position and you will instantly see the new bearing and time to fly.