Europe 24 by NATS shows data visualization of air traffic in Europe over 24 hours, and it is mind-boggling! There are thousands of flights in the air at any one time, and this video does a great job of representing what that air traffic looks like over Europe.
Much of the video takes place over the UK, where you can see the air traffic Heathrow (the busiest international airport in Europe) and Gatwick (the busiest single runway airport in the world) and watch how flights circle around London waiting for a landing slot.
