The purpose of this article is to show the importance of mission planning in a fully automatic flight and the critical role of implementing Sense & Avoid (S&A) procedures at different categories of UAVs. Modern operation of UAVs implies the capability to handle separation provision and collision avoidance in a way similar to the manned aircrafts. The main contributions are: the analysis of the importance of organizing a special course dedicated to the technical knowledge of the procedures for mission planning and utilization of UAVs; a critical analysis of the possibilities of integration S&A procedures for small UAVs and the perspective of obtaining low-cost solution, especially for emerging countries.