Hi Don,
Coming a bit late on this topic, and finding some information already about my recent problem...
I have numerous freeware aircrafts installed, but outside of the P3D folder itself, and I am heavily using the various .cfg files (amongst others the simobjects.cfg of course) to tell P3Dv4where to find 3rd party aircrafts, gauges, sounds, effects, scenery, etc...
Recently decided to check P3D4 stock aircrafts traffic file, as I know from former versions that there are duplicates, and even triplicates of some flights (same aircraft, same D and A airports, sames times, just different registrations, and sometimes two same birds one flying VFR, the other IFR). I altered or deleted 255 flightplans, but using AIFP (j) version, which knows where to find the stock aircrafts, whereas (k) version showed all stock aircrafts red in the aircrafts list, but knew where to find my AI, MP or addon aircrafts (all located into a separate folder, namely P3D_Externals on my system, paths declared into the simobjects.cfg file) if I wanted to substitute...
So far will remain with (j) version, looking for your coming development releases.
And again thank you for this very useful tool!
Blue skies