vintage planes  

I'm unsure at what point this was during the airshow, if it was before or after the show and they were just landing then it's no different than any other airport controlled or not. But if it's during the official show times then there is usually a "Show Boss" that is controlling the show box (designated distance from around the show center). Aircraft would only be allowed in or out if they are part of that portion of the show going on currently, so if this was during the actual airshow these 2 planes should have been doing their "routine" whether that being just a fly by or what not. Aircraft are allowed to land and takeoff as needed during the lulls in the show, but only by approval of the show boss, who should know the schedule and when it's okay to do so.