Kawasaki recently presented a comprehensive development roadmap for its proposed range of piston engines for aircraft at the AERO event held in Friedrichshafen. The company's plan encompasses the introduction of inline four- and six-cylinder engines, including both normally-aspirated and turbo-charged variants. Notably, Kawasaki's roadmap outlines a future path that includes the development of 9-cylinder hydrogen engines, signifying a pivotal shift towards hydrogen technology in aviation. These engines will be based on the design of Kawasaki's motorcycle engines and will incorporate advanced features such as full-authority digital engine controls (FADEC), auto throttle, water cooling, fuel injection, and initially run on unleaded gasoline before transitioning to hydrogen fuel. The engine specifications showcase a diverse power range, starting from 117 hp for the 1.0-litre four-cylinder engine to 680 hp for the turbo-charged 4.5-litre inline six-cylinder engine. Kawasaki's commitment to sustainability is evident through its parallel development of hybrid engines and its vision for a hydrogen-based society. The company aims to achieve carbon neutrality by utilizing hydrogen fuel, demonstrating a positive sentiment towards environmental responsibility. Kawasaki anticipates obtaining certification for the gasoline engines by 2023, while the hydrogen-powered motors are projected to become available by 2035, aligning with the company's long-term sustainable energy goals.