It is always convenient and quicker to use air mode of transport, but it is always accompanied by the drawback that it is a bit expensive and costly as compared to the other modes of transportation used.
Ships are also used to carry goods between places that are separated by vast distances. It is always a lot economical to carry a cargo by ship, although it is often quite slow. For those who can wait for days on end, the sea mode of transportation is the best. But there are a few points that should be borne in mind.
A cargo by ship is going to be amenable to be looted by some pirates. They often operate in syndicates and it is very difficult to avoid them if you wade into their territories. The only way to avoid them is not to go into their waters. The captain and other sailors of the ship carrying your cargo should be well versed in all sea routes.