Aircraft are flying on routes called "airways". SENLO (on the image) is a waypoint, CAN (based at Caen, north of France) is a ground station that helps pilots by sending signals. The white point is the aircraft, the white circles are the past positions. This represents an aircraft as controllers can see them on the radar screen.

Line 1 of the aircraft image:

Line 2:

Line 3:

Line 4:

Line 5:

Line 6:

What to do? Begin by this rule:

There must be a distance of at least, 5 nautical miles between aircraft at the same actual flight level. 5NM are equal to 0.7 inches on the maps
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You can move your mouse on the image above to see some of the things that awaits you... But keep in mind that in the Flash simulation, it is not "like this" all the calculations are done, in order to provide a highly interactive simulation.
Flash animations source files
 
Links to simulation sites, air traffic control, flash