In 1941, Germany surprisingly attacked the Soviet Union. The Russian people were outraged. Everyone wanted to do their part, even hundreds of female pilots. Eventually, through the work of Marina Raskova, three regiments were created, all entirely staffed by women. One of these, the 588th Night Bomber Regiment, was given outdated bi-planes and told to bomb the Germans in the darkness of night. They did their job so well; the Germans began calling them Nachthexen, the Night Witches.

Sources
The Female Soldier
Marina Raskova - Wikipedia
Meet the Night Witches, the Daring Female Pilots Who Bombed Nazis By Night
Night Witches — Film by Gunilla Bresky
Not Just Night Witches
Night Witches
Night Witches: How the USSR’s Female Flying Aces Took the Fight to Berlin
Night Witches - Wikipedia