The discussion is here: http://www.reddit.com/r/movies/comments/28z7co/the_poster_for_brad_pitts_new_movie_fury/
The poster being discussed is here: http://i.imgur.com/GA5Mfad.jpg
Some in the original thread called it a 'Hitler youth cut' that doesn't belong on an American soldier, others said there's nothing really stopping them from getting it. So what is plausible?
While that hair style was definitely more usual in Germany, I don't see any reason why it wouldn't be possible to see an American soldier using it.
GIs used a wide variety of hair styles.
You can see some soldiers getting a haircut that looks like Brad Pitt's here http://ww2talk.com/forums/topic/32300-ww2-haircuts/
Also here http://www.talkingproud.us/Military/Military/FlyingDudleys_files/navyrecruituniforminspect1940s.jpg (those are from the Navy)
And, if you wanna go crazy, you can try a mohawk (specially common between the paratroopers) http://farm9.staticflickr.com/8432/7866122868_9a3112f503_z.jpg