A 23rd-century Starfleet rank or title given to especially senior captains, held by Christopher Pike at the time of his accident and by Garth of Izar.
Fleet captain is a grade used in Starfleet during the 23rd century for captains of particular seniority, standing between captain and commodore.
It is first heard in the Original Series two-part story The Menagerie. Christopher Pike, once captain of the Enterprise, had been promoted to fleet captain before the training accident that left him unable to move or speak, and Commodore Mendez and Kirk refer to him by that rank throughout the hearing at which Spock explains why he has taken Pike to Talos IV.
The other well-known holder is Garth of Izar, in Whom Gods Destroy. Garth was a hero whose tactics were required reading at the Academy when Kirk was a cadet. By 2268 he is an inmate of the asylum on Elba II, where he styles himself Lord Garth and tries to seize the Enterprise.