The last time I remember seeing calculations on this, it worked out that it does use more fuel per kilogram than a cargo plane, but only about 1.5x as much - th

The last time I remember seeing calculations on this, it worked out that it does use more fuel per kilogram than a cargo plane, but only about 1.5x as much - the reason being that the starship spends most of its flight coasting with nearly zero drag, which an airplane has to fight drag in the atmosphere the whole way to its destination.