I get you: anything already being done, of any magnitude whatsoever, is wholly negligible, but anything new, even of radically lesser magnitude, is "not practic

I get you: anything already being done, of any magnitude whatsoever, is wholly negligible, but anything new, even of radically lesser magnitude, is "not practical", purely because it would need to, you know, be done. But... Do you really believe that gigawatts are not delivered via gigawatt-scale transmission lines to wherever they terminate? Where does the power they carry go, instead? Halving the material operating cost of civil aviation while eliminating its climate impact will require temporarily expensive and temporarily inconvenient changes. Like every substantial change, ever. Railway systems have been built. Highway systems have been built. Electrical power distribution systems have been built. Airports have been built. All cost, and all were inconvenient. That did not make them impractical.