The Day the Earth Stood Still (2008) - 4 major mistakes

Revealing: When the guys are seen piloting the UAV's, they are using Saitek X52 Pro joysticks. These are commercially available controllers for Microsoft Flight Simulator. These were obviously used as props. Even if the army did use these for some reason, they weren't turned on in the movie (the buttons glow green when turned on).

Factual error: As Klaatu is walking down the train platform at Newark Penn Station, in the background you can see signs that say "VIA". VIA is the national railway of Canada and does not have a presence in New Jersey. This scene was filmed in Canada, as evidenced by the signs on the platform and the 1950s style streamlined passenger cars on the track. Neither Amtrak nor NJ Transit uses those type of cars in their trains.

Factual error: US UAVs twice attack the aliens with Sidewinder missiles. Sidewinder missiles aren't a normal payload on UAVs, aren't meant to attack ground targets, and, being IR guided, wouldn't be able to lock on ground targets in either event. What is more, their warheads are comparatively tiny, further limiting their usefulness in this task. The most correct missiles to use would be Hellfire missiles.

Factual error: The electrical power grid fails, depicted by a series of shots of city blackouts and equipment shutdowns. When the power goes out, the lights of an oil refinery go out as well as the flare. In actuality the exact opposite happens to a flare when powered equipment such as compressors and cooling devices fail simultaneously. The flare is not an electrically powered device and is designed to stay lit during power outages. All excess pressure is immediately vented to the flare stack within a second, causing an enormous flame and smoke cloud that will be visible for several miles.