So while this sub generally frowns on counter factual or 'what-if's' we can certainly frame this as, how critical for were those carriers which escaped being in port by chance or slight variance in orders.

And in the end the evidence for any great change in the outcome of the war in rather unconvincing.

But first we should establish which ships are in play here. First and foremost is the Enterprise CV-6, she had been scheduled to be in port come the morning of the 7th but poor weather made refueling her escorts and short legged destroyers delayed her arrival.

The other hull, Lexington CV-2 was near Midway Island delivering a Marine Dive Bomber squadron but well within the chance that she could have left later or earlier.

So that is only 2 hulls, Saratoga CV-3 is a much tougher sell as she was coming out of overhaul and only on the morning of the 7th arrived in San Diego to pick up her air group. Hard to accelerate both her yard time and trip to San Diego, and her trip out to Pearl to put her there on the 7th.

The other 4 carriers on strength, the smaller Ranger, and Yorktown, Wasp, and brand new Hornet were all in the Atlantic far removed from the reach of Kido Butai.

So at most if either or both Pacific carriers were damaged or sunk the most that could happen would have been an acceleration of what happened in reality, being the transfer of CV's from the Atlantic to Pacific. Yorktown was first and arrived in San Diego on December 30th to welcome aboard Rear Admiral Frank Jack Fletcher for a memorable association.

Hornet would be next, arriving in late March to take aboard a load of Army B-25 bombers as part of a daring scheme cooked up by Colonel Jimmy Doolittle.

Wasp then after service in support of the British in the Atlantic and Mediterranean made in West in June of 1942 and from there joined Saratoga and Enterprise in support of the landings on Guadalcanal.

While the loss of a hull or even worse two would have made the margin for error facing Nimitz tighter little of the strategic calculus changes. Hawaii must be defended by at least one carrier task force. While Australia and the sea lanes from there to the US had to be protected by another. So in the end all the is impacted was the ability to surge additional carriers to either front or absorb losses and offer battle again on short notice as between Coral Sea and Midway or Eastern Solomons and Santa Cruz. While a concerted attack on either axis would still have been countered by every hull Nimitz could bring to bear thanks to his superior SIGINT support. While CNO Admiral King is sure to demand an offensive meant to secure Australian security and sealines of communication at the earliest possible date. Still within a month or so of Pearl, by abandoning all other commitments for the time being, King could have restored the Pacific Fleet's carrier numbers, but for 18 months there were still no reinforcements coming from US shipyards.

And by early 1943 we face the same end state, with the USN reduced to at best a single carrier operable in the Pacific at a time(in reality Sara and Big E with some overlap but each damaged at different times). And having to get creative to make up a task force, such as when HMS Victorious operated with Sara for several months in the Solomons as a joint force. However by the Summer of 1943 the situation would have begun to turn as the first batch of Essex and Independence class hulls arrived and began to assemble as the great Fast Carrier Force for the first time at Pearl.