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 the alien ship arrives in Washington DC, its shadow goes over the Lincoln Memorial from the bottom of the Lincoln statue to the top. Since the saucer is heading over the National Mall and the Lincoln Memorial faces the Mall, the shadow should have gone from the top to the bottom. (00:21:40)
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: 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.