This is a very interesting and different kind of Potter story I haven't ever read before. I like the combo of HP and Strike Witches. I am kind of a fan of Strike Witches and I like what you've done mixing them. I can't wait to read the next arc. I think it would be fun to see them now a part of the 501st Joint Fighter Wing next. Harry adding more girls in though make it a trial in a way. Not that Harry gets each girl easy. Hermione getting along with Barkhorn would be a fun relationship and Harry's first girl in the 501st is Yoshika would be nice, but up to you.
As for writing my own HP/Strike Witches story. Maybe, I have a lot of other stories I am working on, but I'll see if I can squeeze it in some how.