I moved most all my P3Dv3 addon airports to my secondary drive (E:).  Will the airports have to be reinstalled after I install P3D 4 or can I simply point the sim to the scenery library E: drive?   

I believe you're good to go kenthom. Just try it, you got nothing to lose. Sim will find those airports on their new locations, only thing is... if there's something installed with them into some other folders... like "effects", "textures" etc,...

I didn't catch you that well, so you want to keep both sims or what ? Why did you "moved" things before even installing new v4 sim ? I have installed v4 and it's right next to my v3, which I probably won't use it anymore but I keep it for some slow migration purpose. At first I actually plan to just add v3 directions for scenery in my new v4 scenery.cfg.

gamer19.  I have read the many threads on how P3D works regarding scenery.  I plan to purchase P3D4 but am going to wait for a bit and let many of the issues be resolved.  Also waiting for NGX.   I had most of my addon airports on my secondary and it seemed others were simply using the scenery library to make their airports functional rather than waiting for installers.  It seems logical to me so I am moving them all now.  There are a couple that I am not going to move since they seem to be more complicated in the way they are layered.   

I also will try to point to my V3 dir's that is on the same disc. Starting tonight to see how things work out.

Pls let us know what works and whats no