Shouldn't the title be FLAG of our fathers? I mean the movie is about the men that planted the FLAG in the famous picture taken in Iwo Jima. Although in the movie we learn that it was the second flag being planted on the hill that got in the picture. So maybe that explains the plural of the word flag in the title.
It was a good story, about the lives of the men that planted that flag, but the film was no Saving Private Ryan. Check it out!