One possibility would have a large membrane with wires connected to a pendant load. The wires would be fractal: the lines from each small kite in a unit would

One possibility would have a large membrane with wires connected to a pendant load. The wires would be fractal: the lines from each small kite in a unit would combine to make that unit's single line, and those units' lines would do the same, and so on. In terms of keeping the load balanced, I figure the individual kites can modulate their surface area somehow. Maybe they fold like butterfly wings, or dilate, or have accordion pleats, whatever. Some of them would have motors and propellers for active control. You would also want to allow for flexibility at large scales, by making the connectors elastic or even having motorized spindles. Last but not least, the failure mode of the large structure is to break up into smaller structures. If you allow this to happen in a controlled fashion at the connectors, then the large structure breaks up into functional autonomous substructures. They can eject any damaged parts and reform. - - - - When I say "kite" I mean the form of the airfoil (as contrasted with planes or blimps, etc.), not that they are tethered to the ground. - - - - I don't think the "plank over a ditch" is similar. If anything it's more like a suspension bridge?