Hey guys, check this out - coming soon...
https://www.youtube.com/watch?v=D0Qai4ZRTSA
The thing is you don't build up formations flight by flight. For this you just add planes. They also seem to follow a bit too good but still, if you are smooth, it won't be noticeable.
It may have FSRecorder functionality too but I don't know. It would seem easy to add that if the developer chooses. I would think the hard part of hooking into the sim to place AI planes is done and the rest is just the data you feed it.
Pretty cool!