The challenge is that Structure is such a broad diverse topic in Engineering Science, beginning with geometric and topological physics principles.
Structural Engineering addresses design with solid-phase materials like metals, ceramics, polymers, and so on. “Structure” is of course also recognized in fluid-phase materials, for example vortices. Its standard these days to look at wing in flow as the systematic interaction of both kinds of structure, solid and fluid. AWES pressure fields are therefore “structural”, as mostly maintained by either solid barrier surfaces or kinematic moment. Electrostatic, electromagnetic, and gravitational “structure” can also figure in specific AWES functioning.
Air is just one major structural element of an AWES, if more so with inflated soft kites. Fabric, sticks, and lines are also major structural elements, as is Composite wing in respective AWES architectures. The derivative pressure field and wake “structures” only arise during use. Moving Air (Wind) by itself is not AWES structure.
My favorite solid AWES structure is Earth itself, as an anchor field medium. Vast inflated arch and dome structures can be anchored (“staked out”) by Earth, with no solid flying mass penalty. Earth is the ultimate stable scalable structure for our kites.
Air is effectively free, weightless, and indestructible. Its pressure and vacuum features can be made to disappear and reappear at will, shaped and reshaped constantly. All on a vast scale compared to rigid spars, which may not be needed at all.
How to manipulate objects with structural Air vortices:
Spin up an artificial tornado between two rotors. An object caught in the resulting vortex can be moved back and forth between rotors, according to which rotor is comparatively driving, and which driven. The manipulator vortex can be switched between new rotors or be dragged around by moving rotors.
This is Air as dynamically structural, without envelopes.
A volume of air inside of a larger volume of air, at the same temperature and humidity, is effectively weightless (zero weight on a weight scale). A kite can break its rigid spars, but not destroy its air.
Rod is referring to air as if weighed in a vacuum, or perhaps chemically destroyed, which are clearly the more “fanciful” cases in our AWE context here.
I take fire safety seriously. Kites setting air on fire is a fanciful fear.
Tornados are well known to pick up and set down objects. Oddly enough, I myself was suspended briefly in an F1 tornado at kFarm, as witnessed by Taylor Taylor (“damnest thing I ever saw”). It blew my shoes off, but let me down gently. The idea presented is simply a controllable version of the same basic vortex physics.
According to relativistic physics, a kite does indeed accrue extra mass “at high speed” (not just by ram-air mass). Be careful not to confuse buoyant air “weightlessness” with its mass.
Fluidic Logic is a closely relevant study to air-as-structure. As with kites, its not just boundary structures that count, but also the natural (wake and bulk far field) structures of (air) flow. Payne’s “self-erecting windmills” are dynamically structural fluidic logic devices. We also recall Shannon’s energy-information equivalence. Air structure is information and energy.