This chapter reviews the state-of-the-art and recent advances and applications of wireless charging applied to Unmanned Aerial Vehicles (UAVs), especially as an assisted 5G network. UAV is an aircraft that does not require a human pilot, such as drones, small aircrafts, balloons, and airships. The main goals of the smart city are to optimize the consumed resources, to reduce cost, and to improve interactivity and the life quality of its citizens, by incorporating information and communication technology (ICT) to manage urban life, agriculture, air pollution, traffic, emergencies, energy source and consumption, government, healthcare, water, and others. Energy efficiency is a fundamental issue, generally in the design of any wireless network, and more specifically in a futuristic network system that incorporates UAVs, as essential system elements to provide connectivity within the 5G integrated ecosystem. In recent years, researchers have achieved great advances in the field of Wireless Power Transfer (WPT).