The increasing demand for continuous and reliable air traffic surveillance over remote and oceanic regions has prompted the exploration of innovative solutions beyond traditional radar and satellite-based systems. In this context, High-Altitude Pseudo-Satellites (HAPSs) have emerged as a promising technology capable of extending surveillance and communication coverage within the stratosphere at significantly lower cost and greater operational flexibility. This paper presents the results of Research and Development (R&D) efforts focused on the conceptualization and development of a HAPS prototype serving as a proof of concept to enhance Air Traffic Management (ATM) surveillance capabilities. The study quantitatively examines the HAPS operational environment by classifying and evaluating the geometric, physical, environmental, thermal and atmospheric factors influencing prototype performance. The developed prototype establishes a scalable foundation for future multi-platform HAPS networks, and forthcoming research will focus on experimental validation under real-world conditions and performance optimization to enable integration into next-generation ATM systems.