Carriers

Carriers are a support unit with no attack or defense strength of their own. They do two jobs.

First, they move your jets to a battle: one carrier carries up to 100 jets. Without enough carriers, your jets cannot reach the enemy.

Second, they carry goods for trade between empires.

You do not have to buy them separately: a large jet order offers to include the carriers for them, for the same gold. If your jets outnumber what your carriers can lift, the carrier screen tells you how many more would cover them.

Carriers are very cheap to keep. A common way to earn gold is to set your industry to build carriers and then sell them. This can earn more than producing gold directly.