Researchers at MIT have developed an innovative sodium-based fuel cell technology aimed at revolutionizing clean energy solutions, particularly in sectors like rail transport, regional aviation, and short-distance travel. Led by Professor Yet-Ming Chiang, the team has created a sodium-air fuel cell with superior energy density compared to traditional lithium-ion batteries and without the challenges of extreme temperatures associated with hydrogen systems. Drawing on experience from Form Energy, known for iron-air batteries, the fuel cell's design allows for easy refueling by removing byproducts and adding fresh fuel, similar to hydrogen systems. Operating at moderate temperatures, the cells show great potential for use in aircraft and ships, surpassing commercial lithium-ion batteries in energy density. Safety precautions address sodium's reactivity, while proposals for diluting byproducts like sodium hydroxide aim to mitigate environmental impact. Economic feasibility is supported by sodium's extraction from table salt, making it a cost-effective option. Chiang's involvement with Propel Aero aims to commercialize the technology, with support from the ARPA-E Propel-1K program. Further research aims to enhance cell performance, with initial applications targeting drones and future plans for aviation. The project's goal is to bring a prototype to flight within the next year, showcasing the potential of sodium fuel cells in advancing sustainable transportation.