Sounds like Strike Witches. In a more realistic sense.
The Weaponization of Magical Girls
Unfortunately for them, the magical girls possessed a power that far surpasses that of the technological world.
A single magical girls in the flesh is far stronger than a team of mechanized soldiers.
At first, the losing countries sent their magical girls and woman onto the battlefield.
The allies were unable to deal with this awesome power so they sent their own women onto the battlefield, thinking that it could turn the tide of the war.