Gents,
Discovered this recently - works with the Oculus etc, a cross-platform Peer2Peer network program that FINALLY produces absolutely perfect multiplayer conditions! It allows users to fly together using FSX, FSX:SE, P3D and with X-Plane support coming soon. We've tried it at our military VA and had twelve aircraft in close formation without so much as a glitch or a hiccup.
Well worth checking out, and it's also free and a very small add-on. We're adopting it as our standard multiplayer network, instead of FSX Multiplayer.
http://pmem.uk/joinfs/