Is this not enough to ban flights all over the globe? not just one from US to UK to Europe?
That was the case during the first phase of the covid-19 pandemic and an added internal total lockdown, but mind you that no matter how serious this particular present wave is, no country is going to take those measures any longer, I doubt there'll be any total lockdown in any country as well as a complete international ban.
And mind you that one of the reason why the above won't happen is cause of the vaccines been made available, that's why your thread is somewhat ironical, if there weren't any vaccines soon to be administered to people, then we can talk about lockdowns again plus travel bans, with effective vaccination then there'll be no need to stop people travelling, hindering tourism and affecting the economy negatively.