- During the first battle between the humans and the Navi, the Navis' arrows failed to penetrate any of the human vehicles' windshields. Yet, during the final battle, the Navi arrows successfully penetrate the windshields. This is because in the first battle the Na'vi are firing their arrows from the ground up at the humans, and the arrows would lose velocity due to gravity and be unable to penetrate the glass. However, in the final battle, the Na'vi are firing their arrows from ikran above the humans, so the arrows gain velocity due to gravity.
- During the attack on Hometree, Trudy decides not to fire her missiles and actually retreats in her helicopter (much to the surprise of the gunman who had been firing on the Navi). Wouldn't she have faced some sort of disciplinary action for this? Yet later in the film, she appears to have full access to the guarded prisoners.
- The Na'vi use arrows with feathers. However there isn't a single known feathered creature on the whole of Pandora. They should be visible, at least.
- During the final assault on the Na'vi Tree of Souls, when all the aircraft take off at 0600 hours, there is a short clip of soldiers and officers cheering the attacking force on from the command room. During this cheer, one of the soldiers on the bottom left of the screen punches himself in the head with his own gun and appears to knock his hat off. He looks around briefly to see if anyone noticed, then continues cheering. LOL
- In the scenes where the characters head to the floating islands, we see waterfalls off the islands. Since these islands are not connected to another more elevated landmass, they should not have a continuous water stream, unless there was some form of precipitation, which was not evident in the movie.
- When Jake Sully meets the Colonel and talks about his previous experience, he says he was at Venezuela, to which the Colonel adds that it is a "tough jungle". However, near the end of the film, Jake states that there is no more green on Earth.
- Guns and human weapons fit perfectly in Na'vi's hands and fingers, despite they are considerably bigger than humans. Even when a Na'vi steal a human weapon, suddenly it looks proportionate to his body, when it actually should appear ridiculously small.
- If there were sufficient levels of ammonia, chlorine and methane, as they were mentioned, to make Pandora's air toxic to humans, the air would also be a nearly explosive accelerant when flame is present.
- When they first land to investigate the area, when Grace says "Cut it down, we'll stay awhile", Trudy is not wearing a mask. She would have been dead by the time they got back.
Special thanks to IMDb.