Check out this simulation of worldwide air traffic over 24 hours, from the AirTraffic team at ZHAW School of Engineering. I thought it was pretty darn interesting.
http://www.youtube.com/v/1XBwjQsOEeg&color1=0xb1b1b1&color2=0xcfcfcf&hl=en&fs=1
http://radar.zhaw.ch/
That was crazy. Europe looks like a magnet pulling everything thing into it.