The RAF as an institution had learned the benefit of boom-and-zoom and altitude advantage by the end of the BoB. There is no question of this as it is mentioned in tactical memoranda and pilot accounts of the period. The RAAF also mention it in their memoranda and pilot accounts.
The problem with using boom-and-zoom and the advantages conferred by altitude is that you have to get into a position to do so. When you are the attacker you can usually have the altitude advantage. When you are the defender you often will not have time to gain enough altitude.
This basic truism was demonstrated in the BoB (where the Germans usually had the initial altitude advantage) and in the Commonwealth air forces defensive actions of the PTO/CBI (where the incoming Japanese fighter escorts usually had the altitude advantage).
And even being on the offensive did not always guarantee the initial altitude advantage, particularly if you were escorting attack aircraft since you had to keep them in sight and not be flying so far away (horizontally or vertically) that you had no chance of spotting/intercepting the enemy fighters in time.
I mostly agree with this, but a couple of points.
First, I was bringing up evidence of "boom and zoom" tactics in the CBI specifically, because when discussing why the Hurricane had such poor outcomes in that Theater, I was told by some people that you can't determine effectiveness of an aircraft from operational history, and that maybe / probably, the Hurricane and RAF units were not using the same tactics as the US units were.
I agree with you that they probably did use "boom and zoom" tactics against the JAAF in Burma and India, but in defense of that faction who suggest they may not have done, I will point out something rather surprising that I've already noted in the Mediterranean Theater. Hard won tactical lessons well learned in England did not always quickly make it to the colonial regions. In the MTO for example, British fighter units were not using 'finger-four' tactics until some time in 1942. "Boom and Zoom" was specifically a big controversy in the RAAF in New Guinea, resulting in the death of one beloved squadron leader as the result of the debate, also in mid 1942.
I do not expect that such basic things took much longer than that to reach the secondary and tertiary theaters though, and I expect that they were using "boom and zoom" by the third quarter of 1942 at the latest. I can't say I know that for sure though.
A more nuanced point is that our concept of "boom and zoom" tends to be oversimplified. Air combat tactics are a fusion of pilot training, tactical theory, unit leadership, and the characteristics of the aircraft involved - on both sides. The Thach Weave was viable for the USN in part because USN fighter pilots had a lot of gunnery training. The AVG made early adoption of "boom and zoom" tactics because Claire Chennault was a very charismatic and assertive leader, who had learned this lesson the hard way himself, and pushed it very hard on his pilots.
"Boom and zoom" specifically had many variations, and how it was exactly implemented depended in part on the aircraft and what it's traits were. US and ANZAC fighter units in the CBI and South Pacific learned to push the limits. US fighter units in P-40s, P-51As and P-39s often could not rely on being able to get above Japanese fighters and couldn't refuse combat any time they were in a disadvantage. They learned to use nose-down turns (like what in modern terms is called "low yo-yo"), special 'escape maneuvers', dive and extend, and zoom climbing to come back into the fray ... assuming they still had enough fuel and ammunition and still were still feeling aggressive enough.
This is what Robert De Haven, 10 victory ace with 49th FG (Darwin / New Guinea / Solomons) who flew both P-40s and P-38s. Here he is talking about fighting with the P-40:
"[Y]ou could fight a Jap on even terms, but you had to make him fight your way. He could outturn you at slow speed. You could outturn him at high speed. When you got into a turning fight with him, you dropped your nose down so you kept your airspeed up, you could outturn him. At low speed he could outroll you because of those big ailerons ... on the Zero. If your speed was up over 275, you could outroll [a Zero]. His big ailerons didn't have the strength to make high speed rolls... You could push things, too. Because ... f you decided to go home, you could go home. He couldn't because you could outrun him. [...] That left you in control of the fight."
P-40 had fast dive acceleration and roll at high speed. So with those aircraft, "boom and zoom' often meant just keeping speed up and diving away when you got in trouble. Allison engined P-40s, as we were noting in some other threads, struggled above somewhere between 16-20,000 feet depending on the exact variant, and depending on loadout etc., often had a fairly shitty rate of climb. So they sometimes had to dive away even when enemy aircraft were above them, extend and come back at speed.
IMO pilots flying each aircraft type, and to some extent every unit and even individual pilot, had their own version of these tactics. What "boom and zoom' actually meant was probably different between a P-38, Mustang, Spit VIII, Spit V or a Mohawk IV or a Hurricane II.
