Flight radar 24 is an iphone app that allows you to see where aircraft are on google maps. It shows the callsign, registration, altitude and a lot more. It is a fun app for plane spotters.
Sit on a city roof or at the top of a mountain and as you see a plane fly above you you will know where it’s coming from and where it’s going. Next time I have to pick someone up at the airport I will be using the flight tracker to know exactly where the plane is. Boredom will be of a different type.
The information about what the plane is doing is quite complete. The only thing missing would be a live radio feed of the ATC communications.