Very cool! An interesting camera angle would have been from one of the W-bound walkers as the 3 'devices' flew past (with Snowdon majestic in the background).
What was the black, airship-like dot in the sky to the east?
Even more OT:
Why do people walk up the road from the East? Looks miserable. I assume it's on some useful route, but i'd rather approach Pen-y-Pass from Snowdon or the Glyders.