That has been done (on small scale) - see https://en.wikipedia.org/wiki/Ion-propelled_aircraft https://en.wikipedia.org/wiki/Ion-propelled_aircraft I'm not sur

That has been done (on small scale) - see https://en.wikipedia.org/wiki/Ion-propelled_aircraft https://en.wikipedia.org/wiki/Ion-propelled_aircraft I'm not sure what the achievable efficiencies are, but I think one downside is that they can generate ozone.