I mean, if she's from the French Resistance or Soviet Union's side, then there's no problem as far as history accuracy goes.
She's supposed to be a British fighter, at least that's what they showed in the trailer.
Some of them did appear throughout the war on the Bristish/Canadian side. Most of them never really got into the centric action of the war but we're relayed as a support role (like in the British aviation, if I remember right).
Honestly, even if I do understand why this topic has such a viewed "outrage and disrespect" toward the historical facts, I still think it is a best an inoffensive supplement destined to a pure entertainment goal.