Garrison
Donor
In all seriousness:
1) More and better-trained pilots. Granted fuel is going to be a problem.
2) More fuel.
3) Standardize on a few types, but research and development need to continue.
4) Try for a knock-out blow on Allied bombers to gain some breathing time.
Jets cannot get into service much earlier, a month or two earlier possibly but NOT a year earlier. The Me-163 Komet is not really a bomber-killer unless fitted with photo-optic cells which allow 50mm shells mounted in the wingroots to fire directly up into a B-17 or B-24,
If you have enough well-trained pilots then something like the He-162 Volksjager might help a lot, if quality control can be obtained (hard to do with slave labor).
2) is pretty much impossible after Barbarossa, the synthetic fuel program was directly competing for resources with the immediate needs of the Wehrmacht and they made easy targets for Allied bombers.
3)Is what they did essentially, problem was that long series production meant concentrating on models that were increasingly obsolete.
4) Again they sort of did this against the 8th Airforce, unfortunately it directly led to the P-51 being introduced as an escort, at which point the Luftwaffe was screwed.
The Me-163 is a complete waste of resources and the He-162 only came into being much later as a desperation measure. Post war testing suggested it was an effective plane, but only in the hands of a highly skilled pilot. Slave labour is pretty much a given for Luftwaffe production after 1942, there is no other source of labour.
The reality is that by the end of the war Germany had hundreds of advanced jet fighters just sitting in the tunnels at Nordhausen with neither the pilots nor the fuel to fly them. Technical tweaks in aircraft production are not going to save the 3rd Reich. The 'best' you might do is postpone the end of the war long enough for the A-Bomb to be used on Germany.