Oh! Look at our future plane! It's transparent! And it has moving seats! And funny transparent wireless displays! And the body heat of the passengers lights the cabin!
Seriously, this is silly. People will generally do stuff like this- "car of the future", "house of the future", "boat of the future", "spaceship of the future", that has a lot of "future" gimmicks in it, but in the end turns out to be utterly over-the-top, even for the time period it is thought of in.
Why is Airbus's "airliner of 2050" rubbish? Because it's totally unecessary. You're not going to burn extra fuel for some fancy "transparent fuselage", or a simulated golf game, or the bunch of empty space that you put into the cabin when you gave it that swivel-y seating arrangement.
At the one of the fancy 'Aviation and Defense' shows we have every two years here, Boeing had a huge mockup of the 787 cabin, complete with video screens in the windows, to get an impression of looking outside the aircraft. I was quite impressed by the lavish feel of the mockup, when I noticed a second series of rather less impressive seats a bit further back- a mockup of the coach-class cabin, not that different from the interior of your average 737, etc (I haven't seen a real first class cabin in years, and have never flown first class, so I guess my simple mind didn't recognise the significance

).
Airlines are all about economy. You want to run a business. You want to be, basically, a peoplemover. The "Airbus of 2050" is no peoplemover, it is a gimmick. For that reason, it is likely that the airliner of 2050 will probably be pretty similar to an airliner of today; after all, it has to do the same sort of thing.
It isn't only that airliners haven't changed much in the last 40-odd years, it's that many of
the actual designs that are flying today are roughly 40 years old, and indeed the aircraft can be decades old themselves. The first decades of aviation saw huge advancements, but (in terms of airliners, at least) everything stopped at a certain point- because at that point, they did what they were needed for, in the way that was needed. Going faster, or higher, or carrying thousands of people, or whatever, wasn't necessary, and it wasn't worth the extra cost.
The advancements since then have been mostly related to things like efficiency and safety. So while the airliner of 2050 might not be that different in appearance, concept, or capability to the airliner of today, it could be highly efficient, and comparatively, very safe. Or could even be an evolved version of aircraft we see flying today, just as the highly popular 737 started out in the late 1960s.
And for the same reason, the Reaction Engines A2 would, at best, end up like Concorde. Not many people want to pay that much extra for that fast a flight. Granted, it could try to avoid many of the issues of Concorde, but flight at such speeds will always be more intensive than flight at the conventional high-subsonic speed.