Goods are sent on cargo ships across seas because it is the most economical means of transport.
Road transport.
I have included a number of links. The chief advantage is it is the most economical way of transporting large volumes of oil from the area of production to refineries, which then transport the refined petroleum products to consumers. It is frequently the only practical means of transporting crude oil, in locations, where the local market is insufficient and there are no alternatives (pipeline to markets do not exist). Secondly, tankers are convenient, since they have a number of compartments, whereby they can make a number of pick-ups (liftings) and deliveries. Third, transportation by tanker is convenient since a large tanker fleet exists to transport crude oil. The disadvantages: Potential for accidents and oil spillage. Since the Exxon-Valdez accident, there has been considerable concern about tanker spills. I have included related links on tanker accidents. Note that it appears that there has been over the last 40 years, a decrease in large accidents. Some oil may accidently spill during loading. The tanker in some cases may not be the most economical means. If oil is found where the discovery can easily be tied into an existing pipeline, shipment of crude by tanker may be less economical. You can find more information in the related links.
"economical" has no comparative or superlative form. You would say "more economical" or "most economical."
a car
By vehicle on the island and by air or water craft outside the island are the ways in which Arubans transport goods. Specifically, Aruba is a small island in the southernmost Caribbean Sea. Within its borders, the most convenient and economical transportation means is the network of roads. Beyond its borders, air and water transportation options present themselves.
The most economical transportation in Spain is the bus system. Trains are also inexpensive.
The 1960s used a lot of cars.
um i think it is trains
The most expensive hats are hand shaped in black leather, the most economical is tan suade
moo mein lo ge
eggs