Captain's License

A Captain's License is required in order to captain a ship with three or more crew stations. No matter the number of such ships owned, only one such license is required per account.

Rebirth reward
This item is part of the Rebirth Rewards and was airdropped to all those eligible on September 2nd.

GAO Airdrop
During the 16th Townhall Michael announced that all ship owners would get a Captain's License air-droppped to them in at some (unspecified) point in the future if they would have ships in their wallet that would require them. After that moment they will be sold like any other NFT.