Callsign FDX is FedEx Express
WHAT AIRLINE IS FDX?
FDX is the ICAO three-letter callsign prefix for FedEx Express. When a radio scanner, flight tracker or radar scope shows a flight like FDX123 or FDX45XY overhead, that's a FedEx Express aircraft talking to air traffic control.
Spot one yourself: open the live scope, enter your postcode, and tap any blip whose callsign starts with FDX for its type, registration, route and photo.