In economics, cargo or freight are goods or produce being conveyed – generally for commercial gain – by ship, boat, or aircraft, although the term is now often extended to cover all types of freight, including that carried by train, van, truck, or intermodal container. The term cargo is also used in case of goods in the cold-chain, because the perishable inventory is always in transit towards a final end-use, even when it is held in cold storage or other similar climate-controlled facility.
Multi-modal container units, designed as reusable carriers to facilitate unit load handling of the goods contained, are also referred to as cargo, specially by shipping lines and logistics operators. Similarly, aircraft ULD boxes are also documented as cargo, with associated packing list of the items contained within. When empty containers are shipped each unit is documented as a cargo and when goods are stored within, the contents are termed as containerised cargo.
Seaport terminals handle a wide range of maritime cargo.
Air cargo, commonly known as air freight, is collected by firms from shippers and delivered to customers. Aircraft were first used for carrying mail as cargo in 1911. Eventually manufacturers started designing aircraft for other types of freight as well.
There are many commercial aircraft suitable for carrying cargo such as the Boeing 747 and the bigger An‑124, which was purposely built for easy conversion into a cargo aircraft. Such large aircraft employ quick-loading containers known as unit load devices (ULDs), much like containerized cargo ships. The ULDs are located in the front section of the aircraft.