As Unmanned Aerial Vehicles (UAVs) become increasingly integrated into various commercial and public applications, ensuring reliable and high-quality connectivity is paramount, particularly in Beyond-Line-of-Sight (BLOS) scenarios. With a special focus on 5G cellular technology, this paper addresses the unique challenges posed by UAVs in cellular networks, such as rapid mobility and high-altitude signal degradation, through a comprehensive analysis of field trials conducted on a commercial 5G network. These trials aim to validate the performance of cellular connected UAVs by examining how handovers impact Quality of Service (QoS). The focus is on understanding the link between handover processes and the overall QoS experienced by the UAVs. Through dedicated field trials, we assessed QoS performance metrics, including latency, throughput, and signal strength continuity. The results reveal a correlation between QoS and handover performance, highlighting the potential of advanced handover strategies to enhance the deployment of UAVs in cellular networks.