Comment by bluGill

This might be useful for a tiny island. Ship from a large Caribbean island to a small one for example. The distance means the round trip is day (night?) trip, and there a things you want shipped in every day, but airplanes are expensive. I'm sure there are other niches where there is only a small amount of cargo going from point A to point B as well. However in general the world needs more cargo and so this doesn't make sense for most.