The advent of the Internet of Things (IoT) era has led to a growing demand for widespread connectivity and improved communication methods. Although there are many competent technologies working for the purpose of capacity enhancement and reliability of the communication system, such as Free Space Optics (FSO) and Radio Frequency (RF) technologies, there is still room and need for further improvement. High Altitude Platforms (HAP) have been identified as one of the promising avenues for boosting capacity due to their straightforward deployment, ability to operate smoothly, and their cost-efficient nature. The main idea remains to deploy multiple HAPs in a single network and operate over a region which enables fast, stable, and efficient, thereby bringing additional reliability and capacity where it is needed. In this article, a three-level hierarchical model is considered for estimating the reliability attributes via multiple HAP system for the considered 5G New Radio (NR) communication system. Stochastic modeling and reliability block diagram techniques are used to analyze performance metrics at each level of the hierarchical model, including the reliability function and mean time to failure. Particular attention is paid to the study of multiple HAP system reliability, for which various scenarios of its functioning are presented, such as repairable and non-repairable k-out-of-n models. An analytical study of the proposed k-out-of-n models is presented and validated using Discrete Event Simulation. The presented analysis of the findings obtained indicates a strong correlation between the simulation results and the analytical results. In addition, for the purpose of completeness, the accuracy of estimating reliability and time characteristics for various input data using significant parameters is achieved by using the well-known K-Nearest Neighbors (KNN) technique.