Only half the UK population fly in a given year. That has been true for the last 6 years. What has changed is those who fly have been taking more trips each year. That can change back. The Ryanair model is based on getting the planes used all year.
The UK mostly goes to the Euro Zone for that weekend break. The high Euro makes that hurt every time you have a beer. It also changes the balance of profit growth between EZJ (who report in pounds) and Ryanair (who report in Euors).
The CAA data shows the departures in UK were down 1% on the year before. The sector length is rising quickly for EZJ and RYA as they try to get a bigger market. Now we have the housing crash will will kill of the growth of east european builders flying in and out of the UK. My guess is we will see a small year on year drop in flying in the UK for the next few years. Worst affected is going to be Ryanair.