Airspace Explorer: 3D flight tracking
Most people are familiar with flight tracking tools and apps, such as Flightradar24 or Plane Finder, that let you visualize air traffic in real time.
Airspace Explorer is a stripped-down version of a professional tool used by NATS air traffic control, called "Operational Insight". Perhaps the most eye-catching feature of Airspace Explorer is that it is in 3D, this way you can see how the air paths of different airliners intersect at different altitudes. A rather truthful visualization of how it is in reality, with airliners flying at different heights.
It also includes some additional information about the Flight Information Regions (FIR) and some UK radar data. Military and Emergency flights have been left out.