Every year the Biggin Hill airshow takes place close to London, one of the largest shows in the UK. Apart from hosting this major show (and being one of the premier WW2 Spitfire fighter bases) it is also the location of one of the 4 holding/access points for aircraft coming in to London Heathrow, and much commercial traffic funnels in over there.
I think I am right in saying that there is never the slightest delay to Heathrow traffic as a result, despite parachute drops from 10,000 feet, displays by the RAF Red Arrows aerobatic team, etc. I've heard the commentator occasionally say that some display flying has been slightly curtailed to enable the Heathrow inbound traffic to be uninterrupted. I know London/West Drayton ATC work very hard to achieve it all.
An interesting difference