In this chapter, the authors present a problem of a performance of unmanned aerial vehicles (UAVs) group flights for a solution of different tasks using criteria of efficiency (safety, regularity, efficiency, economy) and criteria of reliability (connectivity, structural redundancy, survivability, and compactness of connections; the relative distance between UAVs; centrality and periphery of UAVs in the group; the level of system centralizing; etc.). It used graph theory for quantitative estimation of effectiveness of UAVs group flight. It presented all types of UAVs connections in the group (a star, ring, tree, with a common tire, mixed, cellular, etc.). The algorithm for finding central drone repeater (CDR) in a group of the UAVs for sending a control signal to other UAVs in the group was obtained. Examples of for determining the central drone and of the optimal topology in a group of the UAVs in flight are presented.