In this thesis, "Design & Reliability Assessment of AEA Propulsion Grid", the development of a reliable and efficient propulsion grid for All-Electric Aircraft (AEA) is investigated to reduce aviation emissions. Our primary objective is to design a lightweight Power Management and Distribution (PMAD) system that meets stringent reliability standards. By analyzing materials, heat transfer, and grid design, we propose optimized grid topologies that balance weight and reliability. The findings emphasize the importance of redundancy and suggest further research into subcomponent failure rates, control aspects, and real-world testing to enhance system reliability and performance. This thesis provides valuable insights into the future of electric aviation, highlighting the necessity for continued investigation and practical application to ensure ultra-reliable electric propulsion systems and make zero-emission flight a reality.