A hierarchical, decentralized controller is synthesized to control a swarm of three unmanned aerial vehicle agents to move in rigid formation on a plane for surveillance. First, lateral dynamic model for an individual agent is derived. Then, assuming constant speed restriction, the control task is approached considering a two-level control structure: low-level and highlevel. A direct model reference adaptive controller is designed in the low-level, while in the high-level a switching logic is used considering different cases for inter-agent distances. The effect of constant speed values of individual agents is discussed in terms of the feasibility of formation during motion. Positive results obtained from simulations for two different reference trajectories consolidate the effectiveness of our algorithm. © 2013 IEEE.