The relevance of the issues considered in the work is determined by the widespread use of unmanned aerial vehicles in human activities, the high accident rate and the need for scientific justification of the cost of their safety when used in various operating conditions, in particular, in systems for monitoring objects distributed in space. The purpose of the study is to develop recommendations for optimizing the costs of protection systems for unmanned aerial vehicles based on a hierarchical risk analysis of threat models. Results include the developed concept of research  which is based on the principle of determining adequate ratios between the risks from threats to aircraft and the costs of their protection. In the process of research, a method and a software tool were developed that allow the construction and analysis of a three-level risk model from threats. At the lower level of this model, risk assessments are determined for private threat models of individual sections of the route, at the middle level the same is done with risk assessments for clusters of private threat models, and at the upper level, maximum risk assessments for the entire route are performed. In the process of computational experiments using the developed method, it was determined, in particular, that the cost of protection for the general threat model exceeded the private and cluster models by 47% and 20%, respectively. The application of the hierarchical analysis method makes it possible to calculate the total risks and evaluate the corresponding cost costs for various modifications of protection systems. The results of the calculation can be used as recommendations when estimating the costs of building a protection system for unmanned aerial vehicles.