The Blue Condor project, a collaborative effort between Airbus, the Perlan team, and the German Aerospace Center (DLR), recently achieved a groundbreaking milestone by conducting the first-ever in-flight measurements of contrails from a hydrogen turbojet engine in Minden, Nevada, USA. This project, aimed at understanding the climate impact of hydrogen-powered aircraft, utilized a modified Arcus glider with a hydrogen engine alongside a conventional kerosene-powered glider. The experiment, which involved seven flights, successfully measured contrails in four flights, focusing on ice crystal properties, nitrogen oxides, and aerosol particles to evaluate hydrogen's climate impact. The research aircraft, equipped with specialized instruments from DLR's Institute of Atmospheric Physics, gathered data on ice crystals, aerosols, and trace gases to assess the environmental effects of hydrogen combustion. The collaboration also included a chase plane equipped with autonomously operated instruments for measuring contrails and emissions. This pioneering research aims to contribute to climate modeling and advance the development of climate-compatible flight technology. Markus Fischer of DLR emphasized the significance of these measurements in understanding the climate compatibility of hydrogen propulsion in aviation. The successful implementation of the Blue Condor project represents a major step forward in promoting environmentally friendly aviation practices. The collected data will be published, allowing for further analysis and insights into the impact of hydrogen-powered aircraft on the environment and aviation industry.