Lightning detection and aviation. View of the Federal Express (FedEx) air traffic control tower at Memphis Airport, USA. Overlaid on this is a frame from the National Lightning Detection Network computer, showing the distribution of lightning strikes (green dots) across the USA. FedEx controllers use this information in planning the most efficient routes possible for their aircraft. FedEx specialize in transporting express parcels and documents, and have their main operating hub at Memphis. 1992.