Compressed hydrogen/fuel cell cars seems to stay at the initial level of non acceptance mostly due to lack of infrastructure, stations to refuel. I think the other drawback is expensive fuel cell technology. If I’m not mistaken, compressed hydrogen stored in well designed carbon fiber tanks have sufficient capacity for range with little weight issues. Perhaps the lighter weight of fuel cells powering a light weight electric motor allows configuring tanks for sufficient range without weight penalties. Initial prototypes of a fc/e-plane Textron/Cessna/ZeroAvia as proof of concept is no small undertaking. It will be interesting if they succeed.