Besides, if you can do it with an electrical locomotive on the ground, the energy conversion to electricity of a power plant should be better than the energy conversion of a jet engine from fuel to movement.
So imo, cheaper seems plausible, energy efficient is a maybe.
It said “cheaper” not “energy efficient”.
Wings are easy, jet engines are hard.
Besides, if you can do it with an electrical locomotive on the ground, the energy conversion to electricity of a power plant should be better than the energy conversion of a jet engine from fuel to movement.
So imo, cheaper seems plausible, energy efficient is a maybe.