Did you read the comparison in fuel consumption to current jet airframes? Almost 10 times more miles per gallon of fuel burn at 460 mph. This makes the airframe capable of transport efficiency of commercial aircraft with a full load of passengers and freight. It is indeed a game changer that can be scaled up! High bypass turbines are possibly at the end of their evolution. The future of aviation is the death of the hub and spoke system with lower cost to go between smaller airports at higher efficiency with the lower associated fuel burn and costs. This is the type of technology that could disrupt the airline industry. As consumer I would much prefer a direct flight instead of being routed thousands of miles and hours out of my destination with associated layovers just to go less than 1000 miles! The hub and spoke system needs to die! For me to fly to Seattle right now I have to drive 40 minutes to 1 hour abs 50 minutes to catch a plane. Or I can catch a flight from Lewiston to Salt Lake City sit a while and catch a flight back to Seattle taking me almost as long as it takes me to drive my car to Seattle. I was able to drive to my local airport in five minutes and be in Seattle in a couple hours...no longer! This is where air travel today is much less a necessary means of travel and will struggle to make a comeback until better efficiencies are discovered and exploited. Business travelers are no longer going to carry the airlines as many have discovered the use of Internet communications made necessary by our current world wide pandemic.
The pandemic may be the biggest disruptor of the airline industry in our history...no one knows the full impact yet.
By the way Airbus lost in court in the EU to Boeing for the subsidiaries provided by many European countries. Just saying no one knows how that will affect Airbus in the future. I am sure your father knows much more than I do about all this and how it might affect the future of commercial aviation. Interesting times to say the least. I believe many of the grounded aircraft will never fly again due to age and the inability for some of the budget airlines to properly maintain them while on the ground.
Oops sorry about the discussion on planes now back to your killer 40 gallon build!