I'm not convinced he was forming up with the B-17. He was way too fast for that. He was clearly pacing the two Mustangs at the same interval as #2 was with Lead. The formation briefing would tell us who was supposed to do what.
…without a visual. The closure rate was way too high for a rejoin. Appears he was watching other fighters and lost situational awareness of the B-17’s position. Then, the gut wrenching sound of impact.
We are in agreement here. Puma has done plenty of join-ups in F-4s and so forth so he knows a thing or two in that regard.
I'll also pass along that I know there are deconfliction rules in place for the show. An example is the Tora! Tora! Tora! Group's.
Dive bombers (Vals) have a hard deck. They pull out above the torpedo bombers (Kates) which have a hard ceiling. Vals and Kates offset from the centerline to the right based on direction of flight.
The fighters (F4F/FM-2/P-40/Zekes) have a high orbit that they maintain.
The B-17 gets the show centerline for the one-wheel pass, also with a hard ceiling.
These rules are tweaked as needed based on airport configuration (single vs. parallel runways, etc.) but you get the idea.
I do not know the rules for the Bombers on Parade but I'm betting the fighters have a floor or offset--if not both.