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.
Most nations own and utilize large numbers of military cargo aircraft such as the C‑17 Globemaster III for logistical needs.
Popular commercial aircraft transformed to a cargo aircraft such as Saab 340A is designed for high revenue and profitability in short / medium haul operations.