Despite expectations of substantial growth in Unmanned Aircraft Systems (UAS, also called drones) there is currently no large-scale system in place to manage UAS operating in shared airspace. Many countries are developing UAS Traffic Management (UTM) concepts which, unlike conventional air traffic management (ATM), seek to foster a competitive market involving many private actors and service providers and which rely on the cooperative and distributed management of UAS. This paper focusses on the economic policy dimensions of UTM. It describes the main participants, activities and commercial interactions of the emerging UTM concepts in the European Union and the United States. Building on these descriptions, we then consider some of the fundamental choices and trade-offs confronting policymakers when developing an economic policy framework for UTM such as: which activities should be competitive; how can access to scarce airspace be allocated in a safe, fair and efficient way; on what commercial terms will data be shared among participants; what infrastructure can cater for large scale UAS operations; and to what extent should the economic regulatory frameworks for UTM and ATM be aligned.