For pilots it is very important to get what is called NOtice To AirMen ‘s before flying. After all we do not want to blunder into a display by the Red Arrows which has happened in the past. The official site is provided by NATS the National air traffic service and after creating an account so it can be seen that you have checked them before departure and you log in here to access the NOTAM menu.
I prefer the RunwayHD app as it is possible to download and display the official CAA charts, so in theory it is not necessary to carry paper charts.
And AirNavigationPro the one I use because although not quite so clever at drawing lines and getting NOTAM’s it does give you simulated radio aids to follow, and even a full glass cockpit display so if all else failed it would be possible to fly and navigate in cloud using it. Not recommended but it could save your life! It also displays the CAA charts if they are purchased.