Any thoughts on the potential of hydrogen powered or hybrid electric aircraft? Indeed material science (carbon fiber, better alloys, etc) are the key to transportation efficiency. These are two of my articles:

https://scottvern.medium.com/will-future-aircraft-run-on-hydrogen-fuel-cells-or-batteries-3703e2281fef

https://scottvern.medium.com/steel-aluminum-or-plastic-in-electric-cars-ea8fe07bc974

I wrote an article once (never published) about "passenger miles per btw" comparisons (expecting trains to win, cars to lose). It surprised me how well aircraft compared, mostly because they usually are filled to capacity, while often buses/trains are not!