"Nachthexen"

During World War II, the Germans called the Soviet Union's female fighter pilots "night witches:"

They often operated in stealth mode, idling their engines as they neared their targets and then gliding their way to their bomb release points. As a result, their planes made little more than soft "whooshing" noises as they flew by.

Those noises reminded the Germans, apparently, of the sound of a witch's broomstick. So the Nazis began calling the female fighter pilots Nachthexen: "night witches." They were loathed. And they were feared. Any German pilot who downed a "witch" was automatically awarded an Iron Cross.