Junkers Ju 87 AKA the Stuka Dive bomber. This plane played a huge role in the early blitzkrieg style German warfare. It's dive siren was there to scare the targets on the ground below. I've read it was very effective on the minds of opposing soldiers.
Germany at war, Signal magazine, 1940. Blitzkrieg. Battle of France. The Junkers Ju 87 or Stuka Sturzkampfflugzeug, or dive bomber was a two man, pilot and rear gunner, German dive bomber and ground-attack aircraft, Signal Magazine 1940. Pin by Paolo Marzioli