Aerospace designs seem to have been reaching their upper limits of improvement, but how can this be you ask? Well, it's kind of like making your street race car go a tenth of a second faster in the quarter mile.
To do this, you either have to add an abundance of horse power or remove 100 pounds.
Unfortunately, there is a huge issue of diminishing returns the closer you get to peak performance.
If you reduce your car too much, all you'll have is a frame, an engine, some tires, and a small platform to place your rear end, all in the name of speed.
The same is true in aviation and aerospace design, and as you know all aircraft seem to be a trade off, and they sacrifice lift for speed, weight for speed, or drag for lift, etc.
Even with the materials of the future that shape-shift, there comes a point of diminishing returns in that game as well.
With these facts known the only answer is to forget about the airplane, we've done most all we can already, and modify the medium in which it is flying through; the air.
Indeed, for the next evolution in Aerospace we will need to figure out a way to modify the airflow, and one way to do this could be through vibrational acoustic sound generation, literally modifying the air molecules as you fly through them.
By changing the density of the air you can create an airplane that has more buoyancy.
You can also make the air less dense that you are flying through no matter which altitude you're at.
Rather than trying to use expensive and exotic materials to make the aircraft lighter, maybe we should change the air all around it.
Please consider all this.