At the French aerospace lab Onera in Le Bourget, advancements in the Gullhyver concept for an ultra-efficient hydrogen-powered airliner are being made. While the industry's focus on hydrogen propulsion has waned, Onera is emphasizing the open-fan engines' noise reduction and fuel efficiency, along with integrating struts into the wing design. The open-fan architecture, supported by CFM International's RISE program, offers potential for more fuel-efficient propulsion systems. Onera's efforts include digital simulations to optimize fan blade shapes for quieter operations and better fuel efficiency, resulting in a 2.5% improvement in fuel efficiency compared to a 2023 design. Additionally, research engineers are addressing the junction of struts and wings to minimize drag and improve aerodynamics. The AWATAR project will utilize Onera's wind tunnel to study the wing's aeroelastic behavior, crucial for enhancing flight performance and sustainability. Despite skepticism from RTX's chief scientist, Onera remains confident in the open-fan concept's viability and its potential to revolutionize aviation with hydrogen-powered aircraft.