The aviation industry is undergoing a significant shift towards sustainability by focusing on energy efficiency. The integration of clean energy sources like hydrogen fuel cells, alongside advancements in propulsion systems and thermal management solutions, is key to reducing carbon emissions and improving operational efficiency. The videocast discussed the latest breakthroughs in energy optimization, showcasing how advanced materials and technologies are reshaping aviation's approach to sustainability. Energy optimization is highlighted as crucial for sustainable aviation, with a focus on innovative engine designs and the adoption of hydrogen fuel cells for clean energy. Thermal management systems play a critical role, especially in hybrid and electric propulsion, by ensuring safety and efficiency. The use of lightweight materials, such as carbon-fiber composites, is emphasized for its potential to significantly reduce aircraft weight and enhance fuel efficiency. However, the challenge lies in meeting stringent safety and durability requirements while advancing engineering solutions. Digital tools like Computational Fluid Dynamics (CFD), Model-Based Systems Engineering (MBSE), and digital twins are driving innovation in energy-efficient engine design. These tools enable precise analysis, seamless collaboration, and accelerated development cycles, ultimately leading to reliable and high-performance solutions. Collaboration across the industry, including partnerships between established companies and startups, is crucial for advancing energy-efficient engines. By combining expertise and resources, these collaborations drive innovation in fuel efficiency, thermal management, and certification processes, shaping a more sustainable future for aviation.