There is no concern about cost. All must be sacrificed to The Environment, which has taken on god like/idolatry proportions for a portion on the population.
With that said, as I have opined before, IF a person wanted electric flight HFC is the best, perhaps only way to do it.
Batteries are a fail based on weight and very poor energy density.
H2 has advantages.
-It will work.
-Quick refueling. The infrastructure does not exist but throw enough of your money at the problem it can be built.
-Adequate energy density.
-It can be made from US based fossil fuels, which are plentiful.
FWIW it seems Moses Lake, just to my north, is becoming an epicenter of e-plane development and testing for some reason. In general I’m not a proponent of the need for it, but I’m glad to see Moses Lake developing notoriety in this field.