Strike Witches: the Jet striker

in 1939 an unknown enemy suddenly appeared on earth, the humanity called them Neuroi. In a blink of an eye, most of Europe was invaded by Neuroi, many families suffer from the invasion, many of them lost their families, home, relatives, children, or hope but then humanity solve their problem, they created something that it can encounter the Neuroi they called them Striker unit, these things can only be used by girls with magic, they soon battle with the Neuroi in Europe but unknown to them the southeast Asia and Oceania was defenseless, the 203rd joint fighter group was then transferred to Brittania