Factual error: When the nuclear bomb is released in Houston, the shot shows an interstate sign with South Houston as the control city. The only interstate running south of Houston is I-45, and Galveston is the control city on all its signs. (01:35:55)
Factual error: For anyone who is in the Air Force or has taken the time to go inside of an E-3 AWACS at an airshow you will note that the AWACS in the movie looks nothing like that of the real life version. There is no position in the back that they sit across from each other sideways as were the non pilots in the scene that the flame engulfed. The only crew that sits like that is the Navigator and Flight Engineer, but these two actors were clearly too far back for that. (00:17:40)
Factual error: When they show the Israeli Air Force with the Arabs, they show Israeli F/A-18s. The problem is that the Israelis do not own or operate any US Navy equipment - only equipment such as F-16s. (01:41:45)
Factual error: When we see the British pilots (with Iraqi pilots) responding to the news of a planned counter-offensive, the British pilot is stood in front of an F-16 with British markings on. This aircraft has never been in service with the RAF or purchased by the British government.
Factual error: Area 51 is located in southern Nevada (the movie acknowledges this), but the security gate that Steve Hiller enters through is shown to be in the Bonneville Salt Flats, which are located hundreds of miles away in northwestern Utah.
Factual error: Aliens are using TV satellites for their secret attack signal, making the TV picture quality poor. David shows the president how they do it by bypassing the curvature of the earth. However TV satellites don't work that way. They are "hanging" pretty much above their broadcasting area totally reflecting and spreading the signal back straight downward to earth. Turning the parabolic mirrors of the satellites to a different elevation would result in no TV signal on earth, not just a degraded one.
Suggested correction: Satellites do both. They both send the signals back down to earth but they also send signals to each other in order for the signal to cross the globe. And in those signals the aliens have hidden their own signal, and that distorts all satellite signals, causing TV's to receive a distorted signal.
Very few satellites directly talk to other satellites. Geosynchronous communication satellites don't. The antennas used for transmitting the TV signal are directional, but while directional antennas send most of their energy in one (or a few) direction, they still leak at least some energy to all directions, so it could still theoretically be used as described. The real mistake though is the aliens have advanced technology, so could easily have deployed a couple satellites of their own to perform this function, so why the need to use ones from Earth? Worst case just send a couple small ships up to act as relays.
It probably saves them time to use the satellites already in orbit. They are on a tight schedule and don't want to waste time and resources deploying their own satellites. Plus it's a small possibility for them that humans can take out their satellites, so hiding it in their own seems perfect.
They could be using the human satellites to disrupt communications or make communicating across the globe difficult to hinder any possible pre-emptive strike by Earth's armies acting in unison while the harvesters position themselves for the first wave of attack.
