The functional capabilities of unmanned aerial vehicles (UAVs) have dramatically expanded, placing substantial attentional and information processing demands on UAV operators. This study utilized a high-fidelity UAV flight simulation to explore the potential for DFAs in UAV control to reduce operator workload and support overall situation awareness. Three levels of UAV automation (LoAs) were compared, including DFA and static high and low level of automation. This research extended a preliminary investigation by Zhang et al. (2018). The present research addressed the limitations of the preliminary study by increasing the sample size and comparing effects of LoAs during ‘easy to hard’ and ‘hard to easy’ task difficulty transitions. Results of this study demonstrated the presence of “out-of-the-loop performance” issues under high LoA. Results also showed some support for use of DFAs to address out-of-the-loop problems in UAV operations. Findings of this study provide some guidance for design of DFAs in UAV control.