The aviation industry is steadfast in its commitment to achieving net-zero emissions by 2050, driving transformative advancements in propulsion technology. Hydrogen propulsion, hybrid-electric systems, and turbo-electric engines have emerged as key solutions in balancing sustainability goals with operational performance. These innovations are supported by progress in aerodynamics, digital simulations, and stringent certification processes, paving the way for a more sustainable future in aviation. While hydrogen holds promise for sustainable aviation, challenges persist. Engineers and regulators must ensure the safety and efficiency of cryogenic hydrogen storage and its integration with existing aircraft systems. Advanced insulation and monitoring technologies are being developed to address these challenges, alongside the implementation of robust safety protocols and regulatory frameworks to mitigate risks associated with hydrogen handling. Hydrogen's high energy density and clean-burning properties make it a vital component for sustainable aviation. Gaseous hydrogen is suitable for short-haul flights when combined with hybrid-electric systems, while liquid hydrogen, stored at cryogenic temperatures, offers extended range for long-haul operations. The industry is focused on overcoming obstacles in cryogenic storage, safety protocols, and system design to realize the full potential of hydrogen. The evolution of propulsion systems involves integrating hydrogen with hybrid-electric engines for versatility and emissions reduction. Three phases of innovation are envisioned: early adoption of hydrogen systems, enhanced efficiency through lightweight tanks, and turbo-electric propulsion using advanced cooling technologies. These advancements aim to revolutionize aviation, making flights cleaner, quieter, and more efficient. The success of hydrogen propulsion hinges on collaborative efforts across the aviation ecosystem. Aerospace companies, startups, and regulators must work together to address certification challenges and ensure safety standards. Digital tools like Model-Based Systems Engineering (MBSE) and digital twins play a crucial role in accelerating development and validating complex hydrogen-powered systems. Partnerships in fuel infrastructure, supply chain logistics, and energy storage are essential for innovation and ensuring hydrogen propulsion meets sustainability targets. By leveraging hydrogen's properties and innovative designs, the industry is setting the stage for a sustainable aviation future.