Ian, yes metal aircraft but units on top of the coaming so mainly perspex surrounding them, especially in the RV. Also the fact I could be picked up on P3i at 4-5 miles was encouraging. Just wish it also worked the other way too.
Re proximity comment, there was only one unit active in each aircraft during airborne testing. When I swapped units I powered one down before powering the other up, it was only on the ground we had two in close proximity.
I must admit I hadn't flown the RV so slow, for so long, to match the Bulldog, for a while!