The demand for using Unmanned Aerial Vehicles (UAV) is increasing in different applications, such as delivery, environmental monitoring, media, and wireless internet access. In these applications, UAVs are enabled by a cellular device and act as aerial users that need to be served by the underlying mobile-wireless network. The large-scale and low-cost usage of UAVs in such applications/services requires a framework that enables the safe and optimal navigation of UAVs over wide areas. Current cellular mobile networks have the infrastructure and the capability for implementing such frameworks. In contrast to other related work [6,15], in this paper, we propose a framework, called PAveMENT, that provides safe and optimal paths for navigating UAVs where: a) they experience reliable and high-quality communications with the underlying cellular network; b) UAVs cannot fly over no-flying zones and interrupt public/private services, and c) UAVs have minimal impact on the ground users of the mobile network. These are important factors from the perspective of a cellular service provider, as the main enabler for navigating UAVs over wide areas. In this framework, providing safe-optimal paths are performed by constructing a graph around the local area of interest to fly over and computing a least-cost path from the source to the destination. In addition, unlike other related work, we use real network performance indicators, and practical path-loss models with proprietary operational parameters to evaluate the performance of this framework.