"An aviation-size, worldwide hydrogen supply and airliners capable of using it are decades and trillions of dollars away. In terms of a timely green return on investment, the money would be much better spent on SAJF, both for capital investments in capacity and for technologies that improve yields and reduce costs." - Alan H. Epstein (professor at MIT)
AW is right that it will take decades and trillions of dollars, but the rewards are large enough to drive such investment. RR is acknowledging the long-term nature of the market and pivoting to shorter-term profit, probably correctly. You will not fly in LH2 aircraft, but your grandchildren will.
