Hydrogen is not “energy dense” liquid hydrogen needs 5 times the volume to match jet fuel, moreover it needs to be compressed and refrigerated, less of a problem at 30,000 ft but critical on the ground, we are highly unlikely to see airliners fueled by hydrogen. Although it would be possible to fill the hold with hydrogen cylinders and carry less paying cargo. For road vehicles battery electric is the technology developing now, are we really expecting a separate distribution system for hydrogen to be rolled out nationwide, although it may have applications in specific places.