One Size Does Not Fit All DLR (Deutsches Zentrum für Luft- und Raumfahrt or German Aerospace Center) and the German Aerospace Industries Association (Bundesverband der Deutschen Luft- und Raumfahrtindustrie; BDLI) present future visions of electric aircraft. These range from a four-seat hydrogen-powered repurposed Pipistrel that nine years ago won the NASA Green Flight Challenge to large, multiple propeller, medium-range airliners. Their White Paper, “Zero Emission Aviation – Emissionsfreies Fliegen” (unfortunately available only in German) promotes the promise of “energy transition in air transport, with the goal of zero emissions,” and claims this is “possible by mid-century but requires a considerable increase in innovation.” Rolf Henke, the member of the DLR Executive Board responsible for aeronautics research and technology, explains, “The time has come to start a new chapter in aviation. Our white paper shows the path to emission-free flying for the ‘Green Deal’ in aviation, which will lead to new technologies, attractive high-tech jobs, fascinating products and the promotion of …