If i, on the other hand, would have been in charge of commanding the Luftwaffe´s war effort by January 1944, then i see myself implementing the following urgent measures:
(i) In view of the USAAF build-up as observed during 1943, except for maintaining an adequate fighter force for the NJGs, I order the prompt and definitive ceasing of production of twin engined fighters to equip dayfighting units; ZG 26 and ZG 76 are disbanded, their pilots and ground personnel sent to the several Jagdgeschwardern fighting the USAAF and RAF.
I´d rather lose 10 Bf 109s or Fw190s on a single engagement, than 10 Bf-110s or Me 410s. Very simple, every twin engined fighter lost in action implies a 100% casualty rate when compared with the loss of single engined toy.
(Not that I agree with the classical account affirming the Me 410 was "uncapable" of dealing with the allied single engined fighters, but that is material for another discussion; it is just that Germany was fighting against all odds and simply could not afford losing so many men).
(ii) Except for maintaining lonf range aircraft for maritime co-operation with the U-boat force and for some very specific long range bombing missions, the production of all bombers is promptly terminated; the pilots and ground perssonel of all Kampfgruppen in service in 1944 are too sent for training as single engined pilots.
If losing both men manning a twin engined fighter in 1944 was a foolish thing to swallow, what of losing the 4 or 5 men manning a He 111, Ju 88, Ju 188, Do 217 or He 177 in such a critical year? You are spilling your valuable and scarce drinking water while you have not yet gotten across the desert. Thirst will likely kill you.
(iii) I would definetly not go for the so called "Baby Blitz" that achieved very little and implied high costs for the Germans.
The adequate implementation of the measures pointed in (i) and (ii) would imply a significant overall improvement of the German capabilities to wage the war in the air. Reichsverteidigung would bring even more horrific memories to the veterans of both USAAF and RAF.
Losses for the USAAF in 1944 were horrible; we are kind of acquainted with this common song "...the germans could not replace their losses while the USAAF could replace its losses easily...". Now wait a minute there. While the assertion might be correct (partially), the willingness to accept a high casualty toll for Uncle Sam has been completely overhyped.
Unlike the soviet ally, the U.S.A. was not a tyranny where the lives of hundreds of thousands of men could be just put in the toilet; so yes, while the USAers could replace their dead easily than the Germans, a better planned and more concentrated German jagdwaffe could have pushed the guys in the USAAF into some filthy dark alley.
Many pilots of the sturmgruppen of JG 3 and JG 300 reported well performances from their mates providing top cover flying Bf 109 G-6 (although their numbers would not be sufficient), try to imagine what the number of available Bf 109s could have been if you cancel all production of bombers and twin engined fighters (and the availability of more single engined fighter pilots).
All the raw materials, engines, spare parts, ammo, fuel, weaponry, workforce and pilots will be devoted for producing mainly single engined fighters and the Me 262: Bf 109 G-6/AS and Fw 190 A-8s and A-9s for the first half of 1944
Bf 109 G-14/AS and G-10 for the second half of 1944 alongside the Fw 190 D and the Ta-152.
But most importantly, a better planned fighter force would help the entrance of the Me 262 in more respectable numbers.
Cheers!