I'm too far away from planes to know, but it's interesting that you can break it down into steps with different requirements & significance. Cruise requires ene

I'm too far away from planes to know, but it's interesting that you can break it down into steps with different requirements & significance. Cruise requires energy density while takeoff requires power density. Additionally, takeoff, being close to the ground, doesn't have that multiplier effect that high-altitude emissions do. So, what I'm really intrigued by is the thought that you could takeoff with chemical fuel and cruise with electric or fuel cells. Or, as you mention, there's always syngas. That might be the holy grail that saves us from ourselves.