But even with all the improvements, actual and potential, the basic design of an airplane remains the same — a tube and wings. “From a basic structure standpoint, a 787 doesn’t look a whole lot different from a 707,” said Jay E. Dryer, who directs NASA’s Advanced Air Vehicles Program.

To achieve the drastic emissions reductions that may be required by the middle of the century and beyond — to make aviation as carbon-free as possible — new “clean sheet” aircraft designs may be needed, incorporating new technologies and approaches. That’s where the Armstrong Flight Research Center comes in, developing technological concepts that manufacturers may one day use in radical new designs.

Not far from the LeapTech truck is another hangar containing a Gulfstream business jet that has been stripped bare and wired with hundreds of sensors. It is a flying technology test bed, and is testing modifications to the trailing edge of the wings. Where a flap would normally be, there is instead a continuous, bent surface, which changes the aerodynamic characteristics of the wing.

The concept is still being developed, but the eventual goal would be wings that could morph in response to real-time conditions. “The idea is to ultimately replace the entire trailing edge of an aircraft wing with technology like this, so you could continuously change the shape of the wing to reduce drag and increase lift,” said Ethan Baumann, chief engineer for the test jet. The technology could also allow the drag and lift forces to be shifted around the wings to avoid overloading, so the wings could be lighter than conventional ones.

The idea behind distributed propulsion is to take the engines from their usual position hanging below the wings and put them elsewhere. Becausee jet engines are complex, heavy devices, distributed propulsion designs almost always involve simpler and smaller electric motors.

“It makes a lot of sense to rethink where you put motors when you design a vehicle from scratch,” Mr. Clarke said.