Unmanned aerial vehicles (UAVs) are increasingly used in various civil applications, including real-time monitoring, wireless coverage, remote sensing, search and rescue, delivery of goods, security and surveillance, precision agriculture, and civil infrastructure inspection. Smart UAVs are expected to revolutionize UAV technology by reducing risks and costs in civil infrastructure. The civil infrastructure sector is projected to dominate the $45 billion UAV market. This survey presents UAV civil applications, challenges, and research trends. Key challenges include charging, collision avoidance, swarming, and networking/security issues. The survey discusses open research challenges and provides insights for future UAV applications. UAVs can be classified based on endurance, altitude, weight, payload, range, fuel type, operational complexity, and applications. UAV civil applications include real-time traffic monitoring, wireless coverage, remote sensing, search and rescue, delivery, security, precision agriculture, and infrastructure inspection. Challenges in these applications include energy limitations, weather conditions, and regulatory issues. Research trends include image processing, machine learning, and the use of UAVs as aerial base stations. Future insights include the need for data fusion algorithms, efficient deep learning solutions, and power-efficient distributed algorithms for UAV swarms. UAVs can also be used for remote sensing, with active and passive systems for environmental monitoring and disaster management. Challenges in remote sensing include hostile environments, camera issues, and illumination problems. Research trends include combining remote sensing with cloud technology and free space optical communication. In construction and infrastructure inspection, UAVs are used for real-time monitoring, power line inspection, and gas pipeline monitoring. Challenges include data processing, sensor limitations, and regulatory issues. The survey highlights the growing interest in UAV applications in construction and infrastructure inspection, with future directions including improved camera stabilization, lightweight solar-powered batteries, and efficient tracking methods for glacier dynamics. The survey also discusses the potential of UAVs in field-based crop phenotyping and the need for advanced image processing algorithms. Overall, UAVs offer significant opportunities in civil applications, but challenges such as energy limitations, weather, and regulatory issues need to be addressed for widespread adoption.Unmanned aerial vehicles (UAVs) are increasingly used in various civil applications, including real-time monitoring, wireless coverage, remote sensing, search and rescue, delivery of goods, security and surveillance, precision agriculture, and civil infrastructure inspection. Smart UAVs are expected to revolutionize UAV technology by reducing risks and costs in civil infrastructure. The civil infrastructure sector is projected to dominate the $45 billion UAV market. This survey presents UAV civil applications, challenges, and research trends. Key challenges include charging, collision avoidance, swarming, and networking/security issues. The survey discusses open research challenges and provides insights for future UAV applications. UAVs can be classified based on endurance, altitude, weight, payload, range, fuel type, operational complexity, and applications. UAV civil applications include real-time traffic monitoring, wireless coverage, remote sensing, search and rescue, delivery, security, precision agriculture, and infrastructure inspection. Challenges in these applications include energy limitations, weather conditions, and regulatory issues. Research trends include image processing, machine learning, and the use of UAVs as aerial base stations. Future insights include the need for data fusion algorithms, efficient deep learning solutions, and power-efficient distributed algorithms for UAV swarms. UAVs can also be used for remote sensing, with active and passive systems for environmental monitoring and disaster management. Challenges in remote sensing include hostile environments, camera issues, and illumination problems. Research trends include combining remote sensing with cloud technology and free space optical communication. In construction and infrastructure inspection, UAVs are used for real-time monitoring, power line inspection, and gas pipeline monitoring. Challenges include data processing, sensor limitations, and regulatory issues. The survey highlights the growing interest in UAV applications in construction and infrastructure inspection, with future directions including improved camera stabilization, lightweight solar-powered batteries, and efficient tracking methods for glacier dynamics. The survey also discusses the potential of UAVs in field-based crop phenotyping and the need for advanced image processing algorithms. Overall, UAVs offer significant opportunities in civil applications, but challenges such as energy limitations, weather, and regulatory issues need to be addressed for widespread adoption.