This paper analyzes a wireless communication system’s performance where an unmanned aerial vehicle (UAV) in a full-duplex (FD) model facilitates two-way (TW) information exchange between two FD ground terminals. The primary focus is to evaluate the outage probability (OP) under the influence of residual self-interference (RSI), a key challenge in FD relay systems. We develop an analytical framework by deriving closed-form expressions for the OP, considering practical channel models suitable for 5G and beyond (B5G) networks. Our analysis reveals that RSI significantly constrains the system’s performance, especially as transmit power increases. Furthermore, the study provides insights into how system behavior is affected by critical parameters such as UAV altitude and carrier frequency.