> How is this supposed to work, china just has a totally not suspicious container ship sitting in every major port not moving or carrying cargo or letting anyone inspect it and nobody notices that its full of weapons?

Actually, exactly like that. It looks completely normal. Container ships are super massive, and generally containers are only searched after they're offloaded, before leaving the port. So they don't get searched if they remain on the vehicle.

> you don't get to just sail your container ship next to a carrier

A lot of drones have surprisingly long range.