This Chinese Google Maps mashup is a simulated map of flights in and out of Chinese airports.
Planes are shown on the map with small red aeroplane map markers. Clicking on any of the plane markers opens an information window with details about the flight. The planes shown on the map are also displayed in a map sidebar. Clicking on any of the planes in the sidebar will centre the map on the selected plane.
The site is only in Chinese.
Hat-tip to Ren for pointing out that this is a simulated map and not a real-time tracking map.