![Air Cargo Traffic by Metropolitan Area | The Geography of Transport Systems](https://i0.wp.com/transportgeography.org/wp-content/uploads/Map-Freight-Metropolitan-2018-1.png?resize=900%2C555&ssl=1)
Source: Airports Council International. Note: Several metropolitan areas contain more than one airport.
Freight activity shows little difference between airport rank and metropolitan rank, implying that, unlike passenger traffic, freight activity is usually concentrated in a single airport. Air cargo operations are consolidated in a few major hubs and gateways. In the case of major hubs such as Hong Kong, Memphis, and Dubai, the airports have a dominant freight orientation with massive dedicated facilities.