  In this letter, we analyze the secrecy performance of a reconfigurable
intelligent surface (RIS)-aided communication system with spatially random
unmanned aerial vehicles (UAVs) acting as eavesdroppers. We consider the
scenarios where the base station (BS) is equipped with single and multiple
antennas.The signal-to-noise ratios (SNRs) of the legitimate user and the
eavesdroppers are derived analytically and approximated through a
computationally effective method. The ergodic secrecy capacity is approximated
and derived in closed-form expressions.Simulation results validate the accuracy
of the analytical and approximate expressions and show the security-enhanced
effect of the deployment of the RIS.
