In my head-canon, essentially all worlds with an A or B port and a reasonably high population have a highport, which is the principal port in the system. All ordinary cargo and passenger traffic is carried on large unstreamlined ships, with streamlined shuttles being used to transfer these between the highport and surface ports near major population centers. Where the volume of trade justifies it, huge container ships handle most of the cargo; these never dock during normal operations, but instead orbit in an assigned stand-off volume and are serviced by specialized container shuttles.