Comment by WalterBright

My father was the navigator in a B17. He said the Luftwaffe would try to sneak up behind the B17, to see if the tail gunner was watching. The tail gunner would let off a few rounds, even out of range, so the tracers would let the Luftwaffe pilot know he was watching. If not, well, another B17 down.

If that didn't work for the 109s, they'd do a head on attack. A head on attack made it very hard for the B17s to hit them, and the closing speed was so fast it would carry the 109s out of range quickly after the attack.

My father said that unlike the buffoonish German pilots portrayed in WW2 movies, the real ones were careful, professional, and deadly. You never wanted to let your guard down around them.