If that link reports problems. it may be because flights that were being tracked are no longer there. Just exit the warnings.
Essentially, you can identify a plane flying overhead, tell what kind of plane it is, where it came from, and where it's going. And that's just for starts.
These shots are from my real home near Philadelphia, Pa. I'd be interested if it works outside the US.
Play around with it. It has a "3D" satellite map to follow a selected aircraft. They warn that it may cause problems, but I had no problems at all.
One last note - It works for free on a computer, but you have to pay to have it work on a tablet.
Hope you enjoy it.
This one's interesting - an Adelaide Australia landing!
What scares me is when you zoom out and see all the planes flying around the world. And that's just the commercial aircraft add in the light and private stuff, 
the military and that is one hell of a lot of flying machines defying gravity. 
