http://www.nytimes.com/2013/12/20/opinion/the-night-witch.html?hp&rref=opinion

The women were part of the Soviet Union’s all-female 588th Night
Bomber Regiment, and among the world’s first female combat flight pilots. In the
dark, they’d cut their engines and fly close to the ground to hit their targets;
the sound made the Germans think of a witch’s broom.