I am not sure you can really consider this "Frist". There is a kid on Youtube that builds stuff. One thing he built was a small fully electric aircraft and flew it. Archive: https://archive.today/Nfx8v From the post: >>On June 5, test pilot Miguel Iturmendi lifted off from Zephyrhills Municipal Airport in Florida at the controls of the Helios Horizon – the first crewed, fixed-wing aircraft ever to fly on solid-state batteries. The flight was neither spectacular in distance nor in duration – it was a series of short tests to validate the aircraft's weight and balance after the new batteries had been installed – but it didn't need to be to make history.