Secure UAV-AV Communications Architecture in Non-Terrestrial Networks: A Review

• Provides an end-to-end review of UAV-NTN-based AV systems, emphasizing UAV-AV interactions within non-terrestrial networks for mission-critical services. • Analyzes key use cases (e.g., emergency response, disaster management, traffic control) and addresses operational challenges in UAV-NTN-AV integration. • Proposes a classification of security requirements (confidentiality, authentication, integrity, availability) tailored to heterogeneous NTN environments. • Critically assesses state-of-the-art security solutions-cryptographic protocols, key management, blockchain, and AI-driven intrusion detection under UAV-AV resource and mobility constraints. • Identifies open challenges and outlines future research directions, providing a roadmap for secure and resilient UAV-NTN-enabled AV systems. Non-terrestrial networks (NTNs), integrating satellites and unmanned aerial vehicles (UAVs), have become integral to next-generation communication systems, particularly in supporting mission-critical autonomous vehicle (AV) applications. UAV-assisted NTNs enhance AV operations by providing extended coverage, real-time responsiveness, and resilience in dynamic, infrastructure-limited environments. However, integrating UAVs, AVs, and NTNs introduces unique security challenges due to their heterogeneous, mobile and distributed nature. To the best of our knowledge, this paper provides the first comprehensive review of secure UAV-AV communication architectures within NTNs. First, it introduces a systematic taxonomy of security requirements and threat models specific to UAV-NTN-enabled AV ecosystems. This distinguishes our work from prior UAV-AV or NTN-only studies. Second, it consolidates and critically analyzes existing countermeasures including cryptographic techniques, blockchain mechanisms, and intrusion detection systems to assess their effectiveness, scalability, and limitations in resource-constrained, latency-sensitive contexts. Third, we propose a novel classification framework for security solutions that bridges architectural and operational perspectives. Furthermore, this work identifies unexplored challenges in resource management, network interoperability, and adaptive security in heterogeneous NTN infrastructures. It outlines future research directions involving quantum-safe cryptography, AI-enabled anomaly detection, and federated learning for privacy-preserving threat response. The finding and critical analysis provided in this paper serves as a foundational resource that guides the design of secure, scalable, and resilient UAV-NTN-AV communication architectures.