The Luftwaffe even had a B17 flying around, these captured planes where mainly used for training purposes, to learn the the good and the bad points. How to attack them without being blown out of the sky yourself.

Robert van der Veeke Basugasubasubasu Basugasubakuhaku Gasubakuhakuhaku!! "Better is the enemy of good enough." Dr. Mikoyan of the Mikoyan Gurevich Design Bureau.