As for the RN, not sure. I know some of the RN's aircraft carrier practices were superior to the americans (storage of AV Gas), their planes were outdated biplanes like the swordfish but compared to some contemporaries like the US Devastator I'm not sure they were all that bad. At least the swordfish got the job done. And Japanese of course took great interest in their success at Taranto and applied some of the lessons learned later on against the US.
To be blunt, there's a good reason why the RN didn't put in an appearance in the pacific until after the Americans won Leyte.
The Royal Navy had three problems during the Second World War. The first was structural: they had built up their numbers across decades, through a careful program of husbanding resources to build new ships constantly while keeping old ones, but this meant many of their ships were old and it also meant that in the event of war there was no practical way to make up major losses and they would have something of a struggle on their hands just keep what they had in service during wartime operations, particularly in the face of combat damage. (The fate of the Home Fleet's heavy units, of which many were paid off to reserve in late 1944 because they'd become decrepit, is instructive.)
The second was doctrinal. The Royal Navy missed the boat on the rise of the aircraft; modern antiair defenses were the exception rather than the rule among their ships, their investment into fighter-direction prewar was miniscule, and the armored carrier had become a technological dead-end by 1940. Only one armored-deck carrier during the war had a hope in hell of stopping a 1000lb AP bomb, and it was Japanese. (
Taiho; and
Taiho's success there is kind of iffy, but possible.) A lack of funds, and the fact that the Fleet Air Arm had been absorbed into the Royal Air Force and only returned to the Navy in the mid 1930s, retarded the development of shipboard aircraft such that the best of the British carrier aircraft during the war, the Firefly, was still no real match for American planes in most respects. And at the end of the war, of all bizarre possible things, the Brits were actually contemplating a
jet biplane carrier torpedo bomber because if you're going to be backward you might as well go all the way. They never made the doctrinal leap to massed carrier striking forces until near the end of the war, and they could not sustain the operational tempo the Americans could.
The third was simple numbers. An IJN fleet carrier had 65 to 55 aircraft and if you had put together every carrier the IJN ever built or tried to build, all in the same place, they would have fielded 1500 aircraft roughly. A USN fleet carrier had 70-100 aircraft, and counting the CVEs if you put them all together then the USN could field well over 8000 aircraft. A British fleet carrier had 48 to 56 aircraft and put them all together and count the CVEs and you get about 1000 planes.
As an example, consider that despite active carrier cover at Anzio and Salerno, the Luftwaffe was able to use Fritz-X guided missiles against Allied warships covering the landings; something that required a multi-engine bomber to orbit at high altitude over the landing force for twenty minutes or so. This despite the fact they were frequently detected on radar while doing so. This simply could not have happened in the Pacific. Even the early-war pre-radar Japanese would have woken up and sent a flight of Zeros after them ten minutes in.
There were things the RN did well; I have much love for the Town-class light cruisers, for example, particularly
Sheffield, and the effort they went to on every level from doctrine to training to produce an oceanic escort force is one of the models of how to attack a tactical and strategic problem. But in general they wandered off the path of innovation and success sometime shortly after 1918 and didn't come back to it until after WW2.
