I'd expect loading+unloading to be similar in duration once the program has developed far enough. The limiting factor that I think is prohibitively limiting st

I'd expect loading+unloading to be similar in duration once the program has developed far enough. The limiting factor that I think is prohibitively limiting starship from dropshipping cargo, is the need for a landing (and launch!) site, an optional SH booster for the return flight and 1200 tons of methalox fuel to get the ship back to base for reuse (4800 with SH booster). So it'd need the rocket equivalent of an airplane carrier, which has not been developed yet.