Research in Unmanned Aerial Vehicles (UAVs) focuses on enhancing autonomy, communication, energy efficiency, and security for diverse civilian and military applications. Recent studies explore artificial intelligence and deep learning techniques for autonomous navigation, obstacle avoidance, and mission planning in complex environments. Energy-efficient trajectory optimization and cooperative path planning are key research areas aimed at extending flight time and coverage. Advances in UAV communication networks, including Flying Ad Hoc Networks (FANETs) and UAV-assisted Internet of Things (IoT), enable real-time data exchange and situational awareness. Blockchain and federated learning frameworks are increasingly integrated to secure data sharing and ensure privacy in multi-UAV systems. These innovations collectively improve UAV intelligence, reliability, and adaptability, supporting applications in surveillance, disaster management, agriculture, logistics, and environmental monitoring.