> We can solve multiple problems at a time It's not "multiple" problems. There's just one: Where do you get energy? Trying to change the fuel (not energy) sou

> We can solve multiple problems at a time It's not "multiple" problems. There's just one: Where do you get energy? Trying to change the fuel (not energy) source of an airplane is the most useless of all the things that should be changed. Remember: The place the fuel is burned makes no difference, what matters is how you sourced the energy, so why go for expensive and complicated hydrogen for airplanes, when the EXACT SAME energy can be used on land?