Secret project? The Black Hawk from Zero Dark Thirty
The level of realism in Zero Dark Thirty left mouth-open to all who we saw the movie. Not only the movements, gear, information about the mission, but the same exact reproduction of the choppers.
Expert sources say that Black Hawk modified in super-silent mode are amazingly similar to the real ones in Op. Neptune's Spear.
It's fascinating the fact that Hollywood did their job, knowing that this helicopters were a secret project. Rotors had been modfied and built from a special material undetectable by radars.