I came across this via the BBC website. A free plane tracker from NATS (the U.K. Air traffic authority). Hours of fun.

iPad only at the moment though.

http://www.nats.aero/ae-home/
https://appsto.re/gb/LQCvab.i
http://www.wired.co.uk/article/uk-flights-radar-nats-airspace-explorer-app

 

Looks cool. Like a fancier, 3Der version of www.flightradar24.com which I normally use to track flights of friends or family. It always amazes me when I see the blanket coverage of yellow planes over London (and all the major cities).