This study attempted to more fully develop the theoretical framework for a single operator monitoring several uninhabited aerial vehicles (UAVs). Twenty-four subjects from the United States Air Force Academy participated in a study to determine the performance effects of managing multiple UAVs. Subjects monitored three and five UAVs simultaneously using the Multi-Modal Immersive Intelligent Interface for Remote Operation (MIIIRO) synthetic task environment. In addition to workload and performance measures, we examined the effectiveness of two types of target symbology (a stylized symbol set and the MIL-STD-2525B symbols) while controlling the UAVs in a simulated task. Results showed five UAVs created a significant degradation in performance as well as significant increase in workload (subjective and objective). Also, MIL-STD-2525B symbols were shown to have significantly better recall than stylized icons as implemented in the MIIIRO synthetic task environment.