Tracking airplanes anywhere in the world just got a lot easier. The U.S. firm Aireon says its new satellite surveillance network is now fully live and being trialled over the North Atlantic. The system employs a constellation of 66 (Iridium) spacecraft, which monitor the situational messages pumped out by aircraft transponders. These report a plane's position, altitude, direction and speed every eight seconds. The two big navigation management companies that marshal plane movements across the North Atlantic -- UK Nats and Nav Canada -- intend to use Aireon to transform their operations. The more detailed information they now have about the behavior of airplanes means more efficient routing can be introduced. This ought to reduce costs for airlines. Passengers should also experience fewer delays. Aireon has receivers riding piggyback on all 66 spacecraft of the Iridium sat-phone service provider. These sensors make it possible now to track planes even out over the ocean, beyond the visibility of radar -- and ocean waters cover 70% of the globe. The rapid-fire nature of the messaging also means aircraft visibility is virtually continuous. Existing data links only report ocean-crossing aircraft positions every 14 minutes.