Unfortunately, different versions of the game are incompatible in multiplayer.
If there's another go at online flying coming, I'd be interested as well. Last time it was great fun.
I'm now currently flying with 1946 version, atlhough I haven't played online since the last aeroscale sessions.
I got the FB+AE+PF combo as well, but I think this single-DVD pack is superior as it's so convenient. Single disc, zero updating, straight to version 4.07m with all the bells and whistles. The 4.08 update is out but I have yet to download it.
If there's any downsides on the whole smash, it has to be the system requirements given in the box, the same as on PF.
When I bough 1946 early this year, this rig I'm using only had 512mb of RAM, on which the game ran, but just barely.
I kept flying with FB+AE+PF until a friend of mine bought a new PC and I bought the RAM off his old machine. Now with 1280mb, the game runs fine.
If there will be online play, I got one request. Make it full realism + icons enabled (at one kilometer was a good setting), please.