Depending on the size and the weight of the products that you are wanting to ship, either could be the most cost-effective option. Smaller items that are not going to take up a lot of space, and can easily be put into an aircraft would be more cost-efficient in the long run. By shipping faster and supplying the item to the purchaser on time, money is saved and earned.
However, much more significant products, such as bulky and heavy equipment are more cost-effective by ship. If you are shipping extremely large and weighty items, then shipping containers will be your best bet.
For those who are concerned with the carbon footprint, cargo planes are the best option. They emit less carbon than a boat but could end up costing more in the long run. The final price tag will be determined by size, weight, and location of where the product is going.