The lecture at the Faculty of Aerospace Engineering in Delft focused on addressing the climate impact of the aviation industry, particularly the challenges posed by contrails and CO2 emissions. While trajectory optimisation for contrail avoidance can offer short-term benefits, it comes with a trade-off of increased CO2 emissions for conventional aircraft. The discussion shifted towards the potential of applying similar trajectory optimisation strategies to future hydrogen-powered aircraft, which do not emit CO2. This approach presents an opportunity to lower the climate impact of the aviation sector in the long term. Despite the nascent stage of hydrogen-powered aircraft development, contemplating their environmental impact now is essential. By considering these questions early on, the industry can shape design choices to mitigate the climate impact of future aircraft effectively. Supervisor Junzi Sun emphasized the significance of this exploration in understanding and steering the aviation sector towards sustainability.