Maybe the para’s from the Dakota were reenactors (Pathfinders). The rest of the para’s were servicemen. There were para’s form at least: the US, Britain, the Netherlands and Germany. This year around 700 of them jumped. Yes, it’s an annual event. It’s always on the saturday of the Arnhem commemoration weekend (= weekend closest to the 17th of september).
The airshow during the afternoon was a one-off-event. It was (just over) 100 years ago that Jan Hilgers made the first powered flight in the Netherlands just north of Ede. He made a couple of hops in his Bleriot XI.