The increasing integration of Uncrewed Aerial Systems (UAS) into controlled airspace presents significant operational and safety challenges, particularly in conflict detection and resolution (CD&R) for Beyond Visual Line of Sight (BVLOS) operations. Ensuring reliable separation management in U-Space requires robust e-conspicuity solutions that address uncertainties in Communication, Navigation, and Surveillance (CNS) systems. This study evaluates the CERTIFLIGHT UTM Box, an e-conspicuity device designed for General Aviation (GA) and UAS operations, incorporating authenticated GNSS tracking, blockchain-based data integrity, and conflict resolution advisory services. Flight validation tests were conducted using a GA aircraft and a UAS to assess the system's effectiveness in detecting and resolving conflicts under realistic operational conditions. The results indicate that while the UTM Box successfully provided conflict advisories, navigation uncertainties and communication delays exceeding five seconds affected its performance. The study highlights the importance of incorporating CNS system uncertainties into CD&R algorithms to ensure safe separation. Future work will focus on refining conflict resolution strategies, integrating advanced filtering techniques to mitigate sensor noise, and enhancing pilot interface design for improved situational awareness and decision support.