Is travel to the UK restricted now?

[RUNFAST11]

Can people still come to the UK from other countries? Or will it be just for business reasons now for the next 4 weeks?

restricted as there's no overnight stays unless for business

The Foreign Office people have Tweeted:

The detailed list of legal exceptions relating to international travel has not yet been published. Please continue to check the guidance page over the next few days for updates.
ow.ly/Au3I30rhZ3c

What about travel within the UK that involves a flight?

What about travel within the UK that involves a flight?

There certainly are domestic flights and people are travelling on them.

I wouldn't expect to be given the third degree on reasons for travel before boarding but you'd need to read up on the local restrictions at each end of the journey to see how your itinerary fits with the rules.