In recent years, interest in techniques and approaches capable of ensuring the efficiency and sustainability of agri-food chains has grown considerably. In this paper, we explore the opportunities offered by the use of unmanned aerial vehicles (UAVs) for precision agriculture. First of all, we provide an overview about the possible alternatives in terms of aerial platforms and sensors for image acquisition. Secondly, starting from the technical constraints, a preliminary cost analysis is carried out. We refer to a hypothetical small-medium farm in the olive sector, which wants to adopt a UAV to make its agricultural practices more efficient. In particular, we make a comparison between two types of UAV, fixed-wing and rotary-wing. The main result of our analysis is that the purchase of a UAV for own use is still quite expensive, especially if the field to be monitored is limited in size. However, the production capacity of the UAV can be better exploited if nearby farms are also served. Finally, we identify the main current limitations of UAV technology in agriculture and the possible challenges that should be faced in the future in order to achieve large-scale spread