Pratt & Whitney has made significant progress in developing a revolutionary hydrogen-combustion, steam-injection turbine engine, known as the Hydrogen, Steam-Injected, Intercooled Turbine Engine (HySIITE). Through a two-year US government-backed project, the company successfully designed, built, and tested critical components such as the combustor, condenser, and evaporator. The innovative engine architecture harnesses waste heat by super-heating water to produce steam, which is then injected upstream of the combustor to improve efficiency, power density, and reduce NOx emissions. The testing results exceeded expectations, showing the engine to be 35% more energy efficient than current models, with zero carbon dioxide emissions and a drastic reduction in NOx emissions. The architecture's design allows for a much smaller core, enabling a bypass ratio of up to 50:1 and fitting within existing narrowbody nacelle structures. While challenges remain, including the need for significant investment in green hydrogen production and infrastructure, the technology shows promise for widespread adoption by 2050. The success of the component-level testing has paved the way for further development, with potential service entry around 2050. Despite the technical challenges ahead, Pratt & Whitney remains optimistic about the future of hydrogen propulsion in aviation, emphasizing the need for continued innovation and investment to overcome remaining hurdles and make sustainable air travel a reality.