From the start of the Pacific War the US fleet contained what are referred to as "fast carrier task forces."  But the formation known as  "The Fast Carrier Task Force" only came into being in late 1943,  after the arrival in the Pacific of the first ships of the new Essex and Independence classes.

This force was the Pacific War's equivalent of the great gun-armed battlefleets of earlier conflicts.  By the time of the Battle for Leyte Gulf it had already proved itself to be one of the most potent instruments in the history of naval warfare  -  obliterating Japanese air power,  and sweeping enemy warships and merchant shipping from the seas,  wherever it had ventured.

It  was divided into carrier task groups,  each group containing typically between three and five carriers,  with each group having its own strong escort - a large number of cruisers and destroyers,  and often two or more of the new fast battleships.

This magnificent force,  as well as possessing unprecedented striking power,  afforded a picture of splendour and beauty not surpassed  -  and perhaps not equalled  -  in the history of warfare:

"The age of steam has afforded no marine spectacle comparable to a meeting of Fast Carrier Forces Pacific Fleet.   Now that the seaman's eye has become accustomed to to the great flattops,  and has learned what they can do to win command of the sea,  they have become as beautiful to him as to his bell-bottomed forebears.  They and the new battleships with their graceful sheer and boiling wake evoked poetic similes  . . "
[Samuel E. Morison 'History of US Naval Operations in World War II'  Vol. XII  'Leyte,'  pp. 86-7]

John Keegan also conveys this well (despite some characteristic inaccuracies in his description)  -

"The majesty of the American carrier groups manoeuvering at sea exceeded even that of the dreadnought fleets.   The spectacle of those great floating airfields steaming upwind . . . . under the vast Pacific sky to launch and recover up to a hundred aircraft  . . . .  surrounded by the cruisers,  destroyers and radar pickets of their air-defence screens,  left an indelible impression of grace and power on all who witnessed it.  Here,  it seemed beyond doubt,  was the supreme instrument of command of the sea,  unapproachable by surface ships,  self-defending against aircraft,  and able to strike at will for hundreds of miles in any direction beyond the circle of ocean it directly occupied."
[John Keegan "Battle at Sea - From Man-of-War to Submarine" p.267  (Published by Pimlico,  London)]

From early 1944 the Fast Carrier Force was known as 'Task Force 58'  when serving under Admiral Spruance's Fifth Fleet, and as 'Task Force 38' when organised as part of Admiral Halsey's Third Fleet.  (Third and Fifth Fleets in general consisted of the same vessels - only their command teams differed).

The nucleus of the Fast Carrier Force consisted of the large fleet carriers of the Essex Class,  augmented by the two surviving pre-war carriers  -  Enterprise and Saratoga  -  and the light fleet carriers of the Independence Class.

For the Leyte operation,  as 'Task Force 38,' and constituting almost all of the US Third Fleet,   the Fast Carrier Force contained nine large fleet carriers and eight light carriers.   Of the nine heavy carriers eight were of the new Essex Class,  the ninth being the old Enterprise (of the Yorktown Class),  a ship with a matchless combat record.