The article discusses the revolutionary HySIITE engine by Pratt & Whitney, which significantly boosts the efficiency of hydrogen-burn engines by 35%. By cleverly utilizing the water released during hydrogen oxidation, the engine reduces NOx emissions by 99.3%. This breakthrough has major implications for the air transport industry, particularly in the context of PtL SAF and Green Hydrogen production. PtL SAF, a synthetically produced liquid hydrocarbon, has the advantage of utilizing existing fossil-fuel infrastructure for distribution. However, hydrogen emerges as a lower-cost fuel at the production level due to the HySIITE process. HySIITE not only enhances engine efficiency and reduces emissions but also tackles contrail formation issues. Comparing energy use data, HySIITE proves to be a game-changer by tripling net energy savings compared to PtL SAF. The article also highlights how re-injecting water as steam in the engine makes gas turbine engines more efficient by increasing density and power extraction in the turbines. Overall, the HySIITE innovation represents a significant step towards more sustainable and efficient air transport, paving the way for a future where hydrogen-powered engines offer substantial advantages over traditional propulsion concepts.