Collecting reliable data over extended areas in rural environments for surveillance purposes requires low-cost and effective technologies. This paper proposes a backscattering data collection system that uses unmanned aerial vehicles (UAVs) to overcome wireless coverage challenges in rural areas. The proposed system provides physical layer security during autonomous data collection, and we optimize the UAV’s trajectory to manage data leakage while taking into account the limited battery of the UAV. Specifically, we aim to maximize the ratio of secrecy across all tags to the UAV’s power consumption while considering constraints such as the UAV’s maximum speed, secrecy rate fairness among the tags and the energy budget of the UAV. Since the problem is non-convex, we apply convex transformation by relaxing certain constraints to obtain a locally optimal trajectory with low complexity. We evaluate the performance of our proposed optimization scheme by comparing it with relevant benchmarks and quantify its complexity through simulations.