I love idiot paper warriors like you. My father flew 50 missions in a P51, and he didn't have quite the contempt for the quality of the Luftwaffe that you do. It is real easy to be snide and contemptuous idiot like you are when it is not your A$$ that is on the line. Great line you've got, willing to kill Poles, Israeli's, Americans, whatever, so long as your fat tail is safe.
And yes, the P51 Mustang was the deciding factor that turned the tide in the air war according to Eisenhower, and when Goering first saw it he was known to have said the jig was up. It's not contempt as you call it, it's simply pride that this nation produced better weapons which ultimately defeated a very evil enemy.