> And the whole thing still has the possibility of being zero-emissions. Well, so does a hybrid plane, if it's fueled with biofuels. Zero net CO2 emissions an

> And the whole thing still has the possibility of being zero-emissions. Well, so does a hybrid plane, if it's fueled with biofuels. Zero net CO2 emissions anyway. I would imagine other emissions are less problematic since it happens far away from populated areas. I'm not sure why hydrogen is desirable. Hydrocarbons have higher energy density and is easier to store and fuel. I can imagine that the closed loop of H2O + electricity <-> electricity + H2 + O is more efficient than the hydrocarbon equivalent. But neither technology is near their theoretical limits, so it's a bit hard to say yet. Regardless, if we build hybrid planes, we can use whatever technology makes the most sense. It shouldn't be too hard to swap out the energy storage mechanism. Who knows, maybe we'll invent a good rechargeable aluminum-air battery and replace everything with that.