So some of you think the Luftwaffe wasn't effective anymore by late 1943? Tell the bomber crews that! Far fom being useless, it was so effective that the daylight bombing campaign actually had to be halted for a time due to the grevious losses the "no longer effective" Luftwaffe was inflicting.
And some of you seem to think the American kids just out of flightschool in 1944 were somehow more experienced? You don't get combat experience in a flight school. American pilots were certainly better trained for landing and formation flying, but in actual combat a green pilot is still every bit as green. There is nothing to replace the "baptism by fire".
The really pivotal battles happened in spring/early summer 1944. This is when the long-range escorts suddenly and unexpectedly (to the Germans) appeared. The result was the inexperienced pilots in the P-38's, P-47's and P-51's slaughtered the inexperienced pilots in 109G-6's and 190A-8's. The bulk of the Luftwaffe fighter strength was geared towards killing bombers; their equipment didn't have the performance to meet the Allies on a level playing field. They were avoiding Allied fighters when possible for more than a year when suddenly that wasn't an option anymore--and it hurt them bad.
By the latter half of 1944 the Germans finally responded to the threat with a new generation of fighters---the 109G-10 and K, and the 190D-9. THIS is when the now experienced Allied pilots began to slaughter the new generation of German fliers. The Allies never gave them a chance and made destruction of the Luftwaffe a priority. With Allied fighters able to range all over Germany and strike "targets of opportunity" on their return flights, the Germans had nowhere to hide, nowhere to train, nowhere to operate in safety. Even then they somehow managed to remain a credible (if diminished) threat until after the Battle of the Bulge.
J_A_B