Return will be in shielded area.
Something like "band saw" where blade will be wire (without movement of course).
Next idea can be self charged power sources with + and - potencial at the end of wires.
Something like charged skies vs Earth during flash.
Levitation using Earth's magnetic field - "electric propeller".
I have idea how to levitate using weak Earth's magnetic field.
It is something like electric propeller - magnetic field line booster.
There is 3 wires (in this case). With no current in wires all is standard, no levitation...