it seems kind of obvious once you realize it. I like it!

totally decarbonized? --> Emissions need to be compensated - what would be equally good for our climate. Saying this, first step shall be substitution of fossil fuel to green fuel derivates. So if we grow our fuel in plantations and fly with this fuel, aircrafts can significantly reduce emissions. And this is a lot easier to achieve (but not as sexy as the advertised project). Counting on only a 15-engineer strong Ascend team for the biggest player in Europe, it is visible that it is only a side project for them... Most start-ups count on stronger manpower making their dreams come true...

This sounds wonderful as long as the flying dewar and all its ancillary lines stay in perfect condition. First few generations for autonomous freight, please.

But does the H wind up getting warmed too much?

Unless you are pulling the hydrogen from the atmosphere your flight time is limited as your supply will heat up, expansion, & looses along the way. Not to mention a big explosion potential anywhere in the system. Maybe try nitrogen, far more abundant, & safe run at 77K with onboard solar powered energy driven liquid nitrogen generator, some storage may be required for night flights.

One caveat is that such a plane would always need to hold a portion of its liquid hydrogen in reserve to cool the powertrain and thereby preserve its superconducting properties. It would seem that for safety's sake, this portion of liquid H2 would probably need to be held in a separate compartment from the liquid hydrogen that is used to power a fuel cell and generate electricity.

Not to be too negative about pointing out the obvious, but cryofuels and passenger aircraft are not a really healthy combination, not to mention the volatility of the fuel.

Agree with other's comments regarding the dangers of using Hydrogen. Just turn back to ALL hydrogen powered rockets require a blow off of gas from storage container; now add a lightening strike, at ANY point in the journey. Yes, agreed that shuts off at launch; but then remember that the rocket is burning it's fuel inside, say five or ten minutes; where the airliner has to run for say up to 12 hours. . . Again look at any container always has a potential to leak hydrogen. Hydrogen leak delays rocket launch; now add 120 hydrogen powered aircraft on ground at airport . . . not worth thinking about. There has to be another solution for such aircraft.

In a road vehicle, please, oh pleeeaaasse!

1 No fear around durability of tanks, I worked on LNG fuel tanks for a long haul trucking, currently being used by Volvo
2 This is super cool but not especially new as NASA and several universities have been working on this for several years and will be implemented in NASA's latest X plane Maxwell
3 If you're worried about lightning strikes you probably shouldn't get on an airplane because there isn't much difference between jet fuel or hydrogen in the event of a spark near a fuel line or tank. Current airliners have robust lightning strike protection.
4 The ecological perils of using biofuels has been well documented and hence isn't being pursued for a reason (it's a stopgap at best)
5 Not sure why people feel compelled to comment negatively on technical subjects they know nothing about. As if the top notch engineer's at Airbus and NASA didn't think of these things LOL