While unmanned aircraft have been in use for decades, their suitability for transporting cargo is only now slowly being recognised. The first prototypes of unmanned cargo aircraft (UCA) are currently being tested. There are two categories of UCA: short-distance aircraft for delivering packages and specialised items like medicines, and UCA for long-distance cargo transport. In this study, the potential of the second category is evaluated from both a technical and a business perspective. UCA can in theory have low direct operating cost compared with manned aircraft because the aircraft can be made simpler and more efficient. They can be more productive because there are fewer scheduling constraints. These advantages especially manifest themselves when relatively small loads are carried. UCA can unlock the economic potential of areas that are not yet linked to the worldwide cargo transport infrastructure. However, there are challenges. The theoretical advantages of UCA have not been proven in practice. A safety record has not yet been established. The requirements for UCA, like payload and range, are unclear so that investing in the development of UCA is risky. Present regulations in Europe and the USA do not allow regular UCA operations.