This article surveys the key issues in UAV communication networks, highlighting the challenges and research directions for developing stable and reliable networks. Unmanned Aerial Vehicles (UAVs) have significant potential in public and civil applications, especially where human safety is at risk. Multi-UAV systems are more efficient and cost-effective than single UAV systems, but they present unique challenges due to their dynamic and fluid topology, intermittent links, and high mobility. Unlike traditional MANETs and VANETs, UAV networks require protocols that adapt to high mobility, dynamic topology, intermittent links, power constraints, and changing link quality. Routing protocols must also handle network partitioning, seamless handovers, and energy efficiency. The article discusses the need for flexible and automated control through Software Defined Networking (SDN), which can help manage network resources and improve security and availability. It also emphasizes the importance of energy-efficient protocols and the need for self-organizing, self-healing networks. The paper categorizes UAV networks based on their applications, mobility, and network architecture, and discusses the challenges of routing, handover, and energy conservation in UAV networks. The article concludes that UAV networks require specialized routing protocols and network management strategies to ensure reliable communication and efficient resource utilization.This article surveys the key issues in UAV communication networks, highlighting the challenges and research directions for developing stable and reliable networks. Unmanned Aerial Vehicles (UAVs) have significant potential in public and civil applications, especially where human safety is at risk. Multi-UAV systems are more efficient and cost-effective than single UAV systems, but they present unique challenges due to their dynamic and fluid topology, intermittent links, and high mobility. Unlike traditional MANETs and VANETs, UAV networks require protocols that adapt to high mobility, dynamic topology, intermittent links, power constraints, and changing link quality. Routing protocols must also handle network partitioning, seamless handovers, and energy efficiency. The article discusses the need for flexible and automated control through Software Defined Networking (SDN), which can help manage network resources and improve security and availability. It also emphasizes the importance of energy-efficient protocols and the need for self-organizing, self-healing networks. The paper categorizes UAV networks based on their applications, mobility, and network architecture, and discusses the challenges of routing, handover, and energy conservation in UAV networks. The article concludes that UAV networks require specialized routing protocols and network management strategies to ensure reliable communication and efficient resource utilization.