Carriers are an uncommon variety of airship but they are the oldest design.
Carrier-type airships were first invented by Gnomish explorers who were trapped in the Turtle Islands after their ship went over the Great Falls. The Gnomish engineer whose name is unknown (for now) created a large bag out of the sails and filled it with the gas of the Methane Trees found in the Great Green Sea. The first true airship is credited to have been built in 650 KR .
Carriers were the first ships to be refit with a balloon to be able to carry them into the air. Many of the older ships still show the scars of where their masts were cut off and sails were attached to their sides to allow them a means of travel in the air. These are the largest of the original "balloon era" airships and the most heavily armored. They are, however, painfully slow but make up for it in the sheer amount of cargo that they can carry.
It was not until the invention of the Fan-Tail Airship, a balloonless design, that Carriers were replaced as the standard, large-cargo vehicle for the Gizerad.