Aviation is undergoing a significant shift towards sustainable flight by exploring alternative propulsion technologies such as hydrogen. While electric flight was once a niche concept, the industry is now rapidly advancing in battery technology, alternative fuels, and hybrid systems with hydrogen. ZeroAvia, a U.S.-based startup, stands at the forefront of this movement with its focus on hydrogen-electric aviation. The company has successfully conducted test flights using a hybrid system combining 'inflammable air' fuel cells and electric motors. To commercialize their technology, regulatory approval is crucial, and a recent milestone was achieved when the FAA agreed on a certification basis for ZeroAvia's 600-kilowatt electric propulsion system. This system offers versatility for use in various aircraft types and power sources, promoting cleaner aviation and paving the way for shorter-range electric flights. The EPS, comprised of bidirectional inverters and a direct-drive motor, is a core component of ZeroAvia's ZA600 hybrid powertrain. The company is also working on a more powerful ZA2000 propulsion system for larger regional turboprops. Collaborating with the UK Civil Aviation Authority, ZeroAvia is focused on developing 'water-powered' refueling infrastructure and certifying its hybrid engines. With plans for retrofit projects and production underway in Washington, ZeroAvia aims to lead the industry towards sustainable and efficient air travel, with thousands of orders already in place for their powertrains and components.