The articles in this special section focus on network-connected unmanned aerial vehicles (UAV) communications. Unmanned aerial vehicles (UAVs) have found fast growing applications in recent years, such as for cargo delivery, precision agriculture, aerial monitoring, video streaming, traffic control, rescue and search, and communication relaying. As the number of UAVs and their related applications grow explosively in the coming years, it is imperative to develop high-performance wireless communication technologies, not only for supporting the ultra-reliable UAV remote command and control (C&C) to ensure their safe operations, but also for enabling high-capacity mission-related information transmission for rate-demanding applications. Integrating UAVs into cellular and satellite networks is a promising solution to achieve the above goals, where UAVs with their own missions could be connected with either cellular base stations (BSs) or satellites as special aerial users, referred to as network-connected UAVs.