It was called flak and was quite effective. The Germans also deployed air to air missiles that were basically rockets with flak warheads on them. See the bomber guns had an effective range of 1000 yards or whatever so if you stood off 1200 yards in your ME-109 and launched rockets that blew up in 1200 yards that worked pretty well.

I've read a couple memoirs of WWII pilots, interesting stuff. I'm pretty sure they're all dead now, whats documented out there is all we'll ever have.

As for effectiveness, well, bomber aircraft losses were tremendous until the end of the war, yet they lost the war anyway. So its hard to say. If you can down 10% of the B-17 per bombing run against ball bearing factories, but still lose the war, was it effective or not? Or looking at the staggering economic and logistics costs of the air war, skipping the air war and focusing on shipping over tanks that don't suck might have ended the war in '44 or earlier, so maybe it was ineffective. Imagine if the winter battle of the bulge never happened because the war was already over by winter rather than lasting till spring. Or maybe no bombing would have meant more hardware would have meant the D-day invasion getting pushed back into the sea Dunkirk II style. Its an evenly balanced enough argument that academics will never lack for discussion topics.

I have a theory that even though the bombers didn't necessarily always hit what they were aiming at, the bombing campaign was important in tying up the Luftwaffe and degrading its capabilities through attrition, thereby hastening achieving air superiority, which provided a major advantage in the later ground war. I'm not sure that better tanks would have made as much difference; and, furthermore, I suspect that the US was able to absorb the costs of the air war without much difficulty, so it wasn't really siphoning resources away from things like tanks.

I'm not sure what to make of the Sherman tank. On the one hand, it was famously under-armored and under-gunned; on the other hand, it was fast, maneuverable, reliable, fuel efficient, cheap to produce, and perhaps easier to ship across the ocean than heavier German-style tanks would have been. So, in the final accounting, I'm not sure if it was really a bad tank or if its shortcomings were justified in the big picture.

I'm not any kind of WWII expert, so please fill me in on what I don't know.

The really crazy thing is just how much more massive the scale of the war on the eastern front was. Some of the Luftwaffe fighter aces racked up 100 or 200+ confirmed kills, primarily against the Soviets. Other pilots who flew close air support on the Eastern Front flew thousands of combat missions, destroying hundreds or thousands of tanks, artillery pieces, and other vehicles.

I doubt that they've all passed away. My great uncle was a WWII B17 navigator, and he's still alive (and quite active).

I met a 94 year old P38 pilot a couple months ago. Still driving his Buick.