Memphis International Airport — Memphis, United States

Memphis International Airport (MEM) built its modern identity around cargo rather than passengers, serving for decades as the world's busiest airport by cargo volume thanks to its role as FedEx's global superhub. FedEx's sorting facility at MEM processes an enormous volume of packages overnight, with aircraft converging from across the country in a coordinated rush that has made Memphis synonymous with express air freight since the 1970s. Passenger traffic tells a different story: Delta Air Lines once operated a major hub at MEM, but the carrier scaled back its presence sharply in the early 2010s after acquiring Northwest Airlines, leaving the airport with far fewer scheduled passenger flights than its cargo operations would suggest. The city of Memphis itself, known worldwide for blues and soul music history and as the home of Graceland, relies on MEM for both its diminished airline service and its outsized logistics economy.