Factual error: As Frederick is explaining to his guests how to use their .45 automatics, he fires one round at a near-by vase, shattering it. However, it leaves no bullet hole in the wall directly behind the vase.
Factual error: When the military are going to attack the flying saucers in Washington D.C., there's some shots where you can see trucks and airplanes in a deserted region. Washington is hundreds of kilometers away from the desert. (00:18:30 - 00:21:10)
Factual error: Karnak was an Egyptian city, not one of their gods.