Deliberate mistake: Near the end of the movie, there is a shot of the "Iwo Jima" with the two recovery helicopters taking off. For a moment, you can see the number 11 on the inboard side of the ship's island, which identifies it as the USS New Orleans (LPH-11), a sister of the Iwo Jima. Admittedly, it was the best the producers could do, since by the time the movie was made, the Iwo Jima (LPH-2) had been decommissioned.
Deliberate mistake: Many times Pocahontas's hair blows in the wind, even though nothing else moves in the shot. From the way her hair moves, the wind should be strong enough wind to move something else, but not even John Smith's hair moves.