The University of Michigan researchers have developed an interactive tool called StratiFly to address the challenge of sustainable aviation by analyzing the most efficient propulsion systems for different flight parameters. Joaquim Martins, a professor of Aerospace Engineering at U-M, highlights the importance of reducing the climate impact of aviation while maintaining its global transport capabilities. The tool compares four sustainable propulsion options: e-SAF, battery-electric, hydrogen fuel cell, and hydrogen combustion, considering factors like weight, efficiency, and sustainability. The study emphasizes that while battery-electric systems are most efficient for short distances due to their weight limitations, hydrogen fuel becomes the optimal choice for longer haul flights. The research team defines efficiency as the amount of renewable electricity needed to produce the fuel required for a specific flight, taking into account sustainability and cost factors. The tool allows users to explore different scenarios and adjust key properties of the propulsion systems, offering insights on potential advancements in energy storage and aircraft design. It also highlights the advantages and challenges of each propulsion option, such as the compatibility of e-SAF with existing aircraft and the efficiency of hydrogen fuel cells in reducing air pollution. The research findings suggest that continuous innovation and technological advancements are crucial for achieving sustainable aviation, with a focus on improving energy efficiency, reducing operating costs, and minimizing environmental impact in the aviation sector. By analyzing various propulsion systems and energy sources, the study aims to guide future developments in aircraft technology for a greener and more sustainable aviation industry.