There is a fascinating app called flightradar24.com
Normally you can't see the UK as it is just a mass of aircraft and you have to zoom right in to actually see any spaces between the planes. But I just took an image a few minutes ago of the UK versus the USA.
It's surprising there are still flights entering and leaving the UK, but look at the USA, what is going on???
That's a lot of essential flying! I hope they're not all coming here