This has to be one of the best uses for Google maps ever. Flightradar24 allows you to view all commercial air traffic in real-time, on a global scale. Is there anything that the internet can’t do?
I can confirm that it does work, I have just stepped outside to view BY2610, a Boeing 757-2B7 travelling from Birmingham to Salzburg pass over my head, magic. What else could Google Maps and an awesome API be used for? If you are aware of other examples then post in the comments.