hey sorry if this is a weird question but i think i once saw this on TIL it was about 3 sisters that would use a tactic of one sister would distract the enemy while the other would turn off their engine and glide over the enemy city to bomb them, i hope i am not too vague, i know there's even a song about them but i can't find that either.
I think I know what you're talking about, assuming that you've mixed up a few things and I'm decoding the mix-up correctly.
First, the song: https://www.youtube.com/watch?v=-16NwCtZv_Q Is this what you mean? If so, read on.
The song is about the 588th Night Bombers Regiment of the Soviet Air Force (Voyenno-Vozdushne Sily), referred to popularly as the Night Witches. It was a female-only unit using the Polikarpow Po-2 biplane in the light bomber/ground attack role. They conducted raids at night, they would indeed idle their engines (not turn off completely) and glide on approach to target so as not to alert the Germans. Allegeldy (and it seems to be a complelling theory), the nickname came from the sound made by the gliding Po-2s, which the Germans associated with the sound of brooms and witches' robes flapping in the wind.
Their targets, however, were not cities, but German land forces, mainly camps, buildings used by administration and support staff and whatnot. The aim of the Night Witches was to instill in the Germans that there is no time of day and night when they can feel safe from death at the hand of the Russians. Essentially, if you failed to hear the wind whistling on the wings, the first and only notice you got that something was amiss would be the explosions of bombs around you.
The regiment was later elevated to Guards status and given the number 46, instead of 588.
EDIT: minor correction of style.