Hi Keith
No - it's not possible to edit the map at all - you can't add or remove airports or runways, or edit VOR's, airways etc.
It's something that AirNav are aware of, and it may change in a future version, but probably not the next one. The map is pretty old now, and is in urgent need of updating, so let's hope AirNav can provide a new one soon, even if we don't get any editing ability.
Rod