While the UAV market is growing exponentially, new architectures are investigated to overcome limitations of conventional platforms. Tethered UAVs leverage vertical takeoff capabilities and flight control flexibility but at the same time eliminate energy restrictions due to battery lifetime. A cable solution is promising as it allows potentially unlimited flight time: vehicles are able to perform longer mission or carry on heavier payloads. These features make tethered UAVs suitable for applications where endurance is key element, such as permanent surveillance, temporary ad-hoc networks, traffic and crowded management and monitoring. Even though tethered UAV technology is still emerging, some industrial applications are already available in the market.