Unmanned aerial vehicles (UAVs) form an important part of the wireless communication systems. Compared to the terrestrial communication systems, these on‐demand UAV networks need to be critically designed. The article highlights, the state of art, challenges encountered and the open research issues in designing UAV‐aided wireless communication networks. The dense heterogenous wireless network scenarios of the present era, poses various challenges to the deployment of UAV‐assisted communication networks. Few of the challenges identified here include best method of 3D deployment of drones, allocation of resources (com‐putational and wireless), optimization of the flight time and trajectory of UAV, handover management, channel modelling of highly dynamic UAV channels in various scenarios of UAV‐assisted networks, interference management, effects of higher doppler shifts in mmWave networks, on‐board energy availability of UAV devicies, etc. The article also aims to give an insight to the future scopes in the designing of UAV‐assisted networks. The budding researchers will be able to identify the open research area of their interest in further development of this technology and thereby contribute to the advancement of wireless communication systems.