I haven't done any calculations, but that will be a significantly sized battery to vertically lift a 4200# airframe, 1300# fuel, and 1800# of people. I suppose it could be recharged during flight by running the electric motor as a generator, but that will take fuel. As for running it on hydrogen, basic fuel energy density calculations of hydrogen vs liquid hydrocarbon suggest there will be a volume issue.... as well as cryogenic/pressure tank issues. Hydrogen might be good for trucks and buses.