Gizmodo provides a lovely video showing all the planes in the air over a 24 hour period. I really like watching the line between night and day move across the planet and the swarms of planes appear as their airport curfews open. It's cool!

If you like this sort of thing, also look at Earth at Night which doesn't move, but makes it night everywhere at once (by gluing together pictures taken at different times) so you can see how we tend to live on the coasts and on rivers.

This one really demonstrates how settlement happened in my corner of the planet.

Kate