Can you remember when this used to occur?
Only if you are getting on in years. It was when they used a Vulcan bomber as a flying test bed for carrying newly invented jet engines at Filton. I was out on the oil delivery when the plane started flying around. I always carried my SLR Agiflez 111 with me and grabbed it quickly as the Vulcan bomber which was used as a flying test bed by Filton, went past.
The motto here being "It is no good to carry a camera if you don't use it"