Starting Allied Carriers
The Allies start out with:
4 CVs (2 Lexington-class, 1 Yorktown-class, 1 Indomitable-class)
1 CVL (1 Hermes-class)
4 Cruiser-Carriers (2 Charlotte-class, 1 Melbourne-class, 1 Vindictive-class)
The new things here are a British CV existing from the start with no withdrawal date (CV Indomitable), but more-so are the four cruiser-carrier hybrids, which can later on convert to CVLs (sadly the Hermes cannot upgrade to a CV and double its a/c capacity). These produce roughly two CVL variants. First is the Charlotte-class. With decent speed of 32 knots, decent armor, and ~1600 AA defense, these things are nice little additions to the fleet. Moreover, they have a relatively quick 4-month conversion time when turning them into CVLs.
The next classes are the Melbourne and Vindictive-class cruiser hybrids, which also convert to CVLs. While these are listed as separate classes, their stats are identical to my eye and there is little difference between them. When converted, their speed drops to 30, they have okay armoring, and decent AA defense (~1000). However, their conversion time is slightly longer at 6 months.
All in all, these are nice little additions, but they are marginal relative to overall Allied might. Nonetheless, they might be the margin of difference in the first 1 or two years. British carriers are a bit slower, whereas all Japanese carriers seem to be uniformly faster. In addition to the above, the allies get additional surface forces in the form of an additional Dutch light cruiser, an additional BC in Force Z, a strengthened and partly more modernized Asiatic Fleet (some more modern DDs, an additional CA). The Marblehead can also convert to a CLAA. French forces are also more numerous, with some submarines, destroyers, and light cruisers at start.
Allied Carriers Additions
Through mid-1944, the Allies receive the following carrier reinforcements:
16 CVs (3 Yorktown-class, 1 Ranger-class, 3 Illustrious-class, 9 Essex-class)
12 CVLs (11 Independence-class, 1 Unicorn-class)
+ Numerous CVEs
This number obviously grows larger beyond mid-44. Of these, the majors are obviously the 9 Essex-class carriers and the three Yorktown-class carriers. Some changes are that the Wasp is a Yorktown-class and the CV Ranger seems more capable and actually arrives in the Pacific. The Ranger-class, however, does have a lower a/c capacity and slower speed akin to the British carriers, nor is it well-armored.
Conclusion:The US gets some upgrades and would theoretically be able to field 20 fleet carriers, 17 light carriers, and numerous escort carriers by mid-1944.
As we know from the analysis above, this is not a quantitative advantage of sufficient preponderance in my mind, especially given how strong his CAP fighters should be. Moreover, there are weaknesses in the Allied numbers: the Hermes isn't a true CVL, the British CVs have lower capacity and are slower, the Ranger has meany weak points and lower capacity. There is basically a high-speed and low-speed Allied carrier fleet and this creates tactical problems. In contrast, all the Japanese carriers excepting the Junyo-class are 32 knots or higher, meaning they are all as fast or faster than their Allied equivalents. They can operate with complete unity and uniformity - this is a great strength!
This necessitates attritional tactics in the early game, but not in a way where we can afford parity in losses. Attritional tactics must result in inordinate damage to the enemy, otherwise they will not be worth it, as later game invasions require domination of the local area. Parity of losses would fail to provide that. The Allies over the coming year must develop a way to seize the strategic initiative and force the Japanese to react in such a way as to place their forces in areas of tactical disadvantage. I feel John always likes the idea of charging in with his forces and should there be appropriate bait, he will come; it remains to be seen if he will eventually combine his carriers and always use them as such or continue to operate them somewhat separately.