The Soothsayers of Doom should consider that 30 years ago Lockheed developed a viable concept hydrogen powered aircraft of 300 plus seats.
The project didn't proceed as the cost of producing the hydrogen significantly exceeded the then price of oil at US$7.00 per barrel! The project was finally shelved in 1998 when the price of oil dropped to US$10 per barrel.
My guess the Skunk Works may well be dusting off the file again.
Woomera