People didn't really know we were resuming flying though.
Outside of work emails, I have seen NOTHING indicating we were starting flights again today.
So maybe NOW people see it in the news or whatever and then they start to book flights again and travel.
Or maybe domestically people don't have much reason to travel (since we can't spend the night somewhere yet except in the "bubble"), yet people really want to get out of the UK, so maybe as international flights start they will be more full.