Dave Demerjian in Wired:
Aspiring scientists from the Zurich School of Applied Sciences have built a video simulation that displays the flight path of every commercial flight in the world over a 24-hour period. There isn't much of an application for it, but it sure is cool to look at.
While the map may look complex, Dr. Karl Rege tells us he and his team found it surprisingly simple to assemble using data readily available on the internet.
“We used a commercial website called FlightStats to gather global flight and schedule information,” he says. “So there was no need to contact the different airlines.”
The team mined FlightStats for the departure and arrival times of every commercial flight in the world, then plugged it all into a computer to assemble their simulation. For the sake of simplicity, they assumed every plane traveled at the same speed and every flight took the most direct route to its destination. Then every flight was assigned a position on a Miller cylindrical projection, which is similar to a Mercator Projection but doesn't distort the poles so much.
More here.