Abstract: Unmanned Aerial Vehicles (UAVs) have been extensively utilized to provide wireless connectivity in infrastructure-free areas, enhance network capacity and provide support for peaks or unexpected surges in user demand, mainly due to their fast deployment, cost-efficiency and superior communication performance resulting from Line of Site (LoS)-dominated channels. In order to exploit the benefits of UAVs as base stations or relays in a mobile ad hoc network, a major challenge is to determine the optimal UAV placement and relocation strategy with respect to the mobility and traffic patterns of the ground network nodes.