Passengers account for most airline business. Airlines also carry a significant amount of freight, for products where speed of delivery is more important than the cost. In practice, this limits airfreight to fairly small amounts of expensive materials. The most common movements are documents and parcel delivery, with carriers such as Federal Express and UPS.
There are three types of air transport:
Regular service: major airlines use the cargo space in passenger aircraft that is not needed for baggage.
Cargo service: operators run cargo planes on regular schedules. These are public carriers, moving goods for any customers.
Charter operations: where a whole aircraft is hired for a particular delivery.
Air transport requires transfers to other transportation modes and has higher costs.