Unmanned Aerial Vehicles (UAVs) are increasingly being deployed in mission-critical scenarios such as disaster management, surveillance, and remote logistics, where human presence is either unsafe or impractical. These vehicles usually come with some sensors and typically communicate the sensors’ data to a Ground Control Station (GCS) over wireless channels, which are inherently vulnerable to security threats, including eavesdropping, data manipulation, impersonation, and denial-of-service attacks. Moreover, the constrained computational and energy resources onboard UAVs limit the feasibility of traditional cryptographic protocols. In this paper, we propose PSKA-UAV, a lightweight mutual authentication and secure communication protocol that uses symmetric cryptography based on a pre-shared key. The protocol is structured into two phases– mutual authentication with session key generation and secure communication uses SEASHA3 for encryption to maintain efficiency. Through detailed experimental analysis, we demonstrate that PSKA-UAV achieves strong security properties while significantly reducing resource consumption, making it well-suited for secure UAV communication in adversarial and resource-limited environments.