I've not seen any of the media give out the full set of rules, so here is a link.

Yet again it is not entirely clear which are enforceable rules and which are guidelines.

https://www.gov.uk/guidance/new-national-restrictions-from-5-november

Travel
If you live in England, you cannot travel overseas or within the UK, unless for work, education or other legally permitted reasons
Also there is now a fine if you go on holiday,Those in breach of the rules could be hit with penalties starting at £200 and increasing to a maximum of £6,400.

Oh right so what are those things flying in the sky and why are the airports still busy?

Yesterday was the first day of the new lockdown and I expect flights will get fewer and fewer as they did during the first lockdown. People already abroad will have to come back so some flights will continue for now.

It says you are not allowed to travel abroad for a holiday which is fair enough.
But let's say you have a second home abroad, and the country that home is in, you are allowed you to access that home, who can stop you going there?

If you let it out or own it as an investment then checking it out could be classed as business travel.

Otherwise they can stop you travelling.