We tried some formation flying with 2 different APM equipped planes.
Both were loaded with AP v2.76 and the same exact mission except for the chase plane flying 20m higher than the target plane. Both planes had cameras in, a Mobius HD Cam and 1.3GHz video link in the chase plane.
In the video I first flew in FBW-A mode then in full AUTO.
We found that the distance between waypoints was too close at 600m as there was not enough time to catch up before the next turn when a plane fell behind or pulled ahead. Due to the variability of the airframes, getting the airspeed synchronized was troublesome as was their turnrate.
We did manage to get some air to air video but our fun was cut short by Phil's plane stalling on the downwind turn with Ardupilot ramping up the throttle too slowly and not being able to recover from the resultant spin, the crash is in the video.
Will try again soon.