Germany was beaten by fall 1944. After that the end was inevitable. The only real question was the cost of prosecuting the war to the end. As with the above posts, I don't think it would have been possible ... unless perhaps something drastic changed in early 1943.
If they has fielded the me 262 in early 1943 in some strength; if Hitler had been more concerned with his people on the Russian Front; if the Type XXI U-Boats had been avilable in numbers at that time (manned, ready, and deployed); perhaps if the Germans had knocked out the British radar and stayed with it as it was rebuilt ... there is a whoile raft of what is that would have to have been seen to in order for the course of the war to have changed.
Given Hitler's nature of keeping the men around him fighting among themselves and not listening to the mlitary advice of his professional military planners (recall that he himslef was a Corporal in WWII, not an officer)... I can't see a way for him to spontaneously turn from a self-centered egomaniac without a conscience into an effective military leader who did proper planning and then carried out the plan.
It seems like a premise somewhat in line with the one here
http://www.ww2aircraft.net/forum/aviation/eastern-front-closed-spring-43-a-43115.html would apply. At least as far as the dead of Hitler and a number of other high ranking Nazis and the replacement with a military government that actually had some practical tactical and strategic mind to manage matters. That and it happening in 1943, early enough to actually make some difference.
But there's that exact sort of drastic change in early 1943 you mention.
The real killer for the germans by the latter part of 1944 was not strategic materials, though that was bad enough. it was manpower. They were scraping the barrel by late '43. by late '44 they were down to the old men and boys. In the air, no amount of whiz bangery could escape the fact that their training regime was in tatters, and not recovering. Against the second gen jets like the Meteor F8 and Vampire, Sea Venom they didnt stand a chance, unless they could recover some skills in their mainstream pilots
A military government (a competent one at least) may have gone some way towards reforming the crumbling (and already flawed) training system.
That said the Meteor F8 and Venom are rather out of the question, even the F4 would be pushing things. Vampire and improved F.3 certainly. (long chord nacelles with 2,400 lbf Derwent IV engines) Putting Goblins in the Meteor might have pushed it closer to the F.IV, but unless Rolls Royce started license building them or they expanded dramatically some other way, I don't see how that would be practical without severely curtailing Vampire production. (Nene and Derwent V would take a good deal longer to get mass production ready, and structural modifications for the Meteor IV would delay production as well)
The P-80A would still be notable though, and longer ranged than the Meteor or Vampire.
The Me262's range limitations were not due to fuel quality, they were due to the engine's performance. No first generation jet engines offered their aircraft significant ranges. The Me262 did have decent armor, however the engines and the poorly protected fuel tanks were an issue. The problem here, is that once you start loading the Me262 down with quantities of armor, you're going to suffer a penalty in performance. And the Me262 did have a good rate of climb to begin with.
As far as armament goes, how can you improve on the Mk108?? Those 4 30mm cannon were devastating to anything they touched. The main drawbacks to the 30mm, was ammunition capacity, range and rate of fire. Perhaps consider 4 20mm: the Mg151/20 was lighter, had a higher rate of fire and allowed for a higher ammunition store. The A-1a/U1 and A-1a/U5 were good ideas, but I think that too many weapons in the nose actually limited their effectiveness.
Lighten the nose armament and you need to add ballast (or added armor for the same purpose). As it was, the Me 262 was too tail-heavy to use the rear-most tank without bombs to counter-balance the front. Loading the nose with 3 (four if they fit) heavy MK 103s might do it, though I'd think adding nose racks and plumbing for drop tanks on fighter models would have been more useful. (use the external tanks as ballast and burn off the rear tank first before switching to drops)
A BMW 003 powered Me 262 derivative should have been significantly lighter and less fuel hungry without disturbing CoG (unless I'm mistaken, the swept back wings positioned the engine mounts very close to the center of gravity, so swapping wouldn't change much). Throttle response, reliability, TBO, and total engine life were all better as well. Lower empty weight would mean potential for shorter take-off and landing runs too, even without improvements in thrust/weight.
The Jumo 004D and E models also improved fuel consumption somewhat as well as thrust, altitude performance, lifespan, throttle handling, and reliability.
Focusing on Me 262 production may have made more sense overall than attempting to divert resources to the He 162 at all ... or any of the competing projects.
Presumably this accomplishment includes greater then historical damage to Soviet alliance air forces. How much greater would determine Luftwaffe planning for 1945. For instance, was 1944 Germany able to effective protect synthetic fuel production plants? Is anti-communist alliance able to retain Romanian oil fields? How about Estonian shale oil mines?
Dispersed production using smaller scale fischer-tropsch synthetic fuel plants would have helped offset things to some extent too. (we discussed the possibility of considerably higher yields with shifts towards non-gasoline fuels -alcohols, etc- but that would be more limited with the existing mid/late war infrastructure, still some blends of higher yield synthetic products may have been possible while still meeting existing fuel grade standards close enough)
Feedstocks for such plants could be any sort of coal, oil, natural gas, or biomass (wood, various types of agricultural or municipal waste -some more useful than others) though transportation to get the feedstock to the dispersed sites might complicate logistics with a shift that late. (more centralized production to more dispersed, though potentially shorter transport lines from factory to fuel depot or even more direct routing to where fuel was needed nearest to any given factory)
There never seemed to be a contingency plan to fall back on if any of these adventures failed. Adventures = Battle of France, Battle of Britain, invasion of Russia, etc. etc. etc.
And this blind faith that the Fatherland will prevail in the end, continued all the way until the Red Army was running through the streets of Berlin...
Unrealistic planning and leadership that likely wouldn't have been shared by a military government resulting from a coup. (or some non military ones with similarly practical, competent shifts in leadership) A better 'what if' in that case would be such events occurring before the Battle of Britain and re-evaluating the entire situation along with potential contingency plans. (starting in 1943 leaves an interesting situation too, but certainly far worse and more limiting)