Have some circumstance come about where the Lexingtons,
Kaga,
Akagi,
Furious,
Glorious, and
Courageous are either not started at all, or finished as surface combatants. No navy therefore gets experience with large aviation ships, and naval aviation's influence during the interwar years is greatly dimished. The USN ends up operating ships no larger than
Ranger, and a lot of the tactics and technology never get developed as in our timeline. Roosevelt never moves the fleet to Hawaii, there is no major loss of surface combatants right at the start of the war, and carriers play a support, rather than primary role during the conflict. There are larger carriers built during the war, but without the experience of the Yorktowns, these vessels are not the equal of OTL Essex class, and are nowhere near as numerous.
At the end of the war, the surface ship institution is still firmly emplaced; first generation cruise missiles such as the Loon give the at least nominal capability to hit targets far beyond the range of guns, and thoughts are already turning to using intercontinental ballistic weapons and later SLCMS such as the Regulus. All six Iowas have been built, all the Alaskas, and production continues with the Des Moines class and Worchester class cruisers; emphasis for future construction is aimed at ships of no larger than CB/ Des Moines size to save on manning costs. The USN's carrier force principally consists of CVEs suitable for trade protection and not capable of operating jets. Even in OTL, the Navy was hard pressed in the early postwar years to operate any meaningful CV force, and things don't go any better here. There is no powerful
naval aviation lobby to press for large and expensive attack carriers and the development of aircraft for them. There are no large numbers of Essex class ships sitting in mothballs ready for rebuilding.
The Soviets embark on a major surface warship program to match the US, and introduce large numbers of Sverdlov cruisers for service as raiders. Even in OTL, these were a headache for the Royal Navy, which did not have a large carrier force postwar.
Vanguard was recommissioned in OTL as an countermeasure to these ships, being considered more effective in that role than aircraft of that time.