Factual error: Anytime a character fires a missile at an airborne target, it's invariably from an M136 antitank launcher. The M136 is designed to hit relatively slow moving ground vehicles and is useless against fast moving airborne targets. (This is because used M136 tubes can't be reloaded and are very cheap to use as props).
Stargate: Atlantis (2004)
1 factual error in show generally - chronological order
Starring: Jason Momoa, David Hewlett, Joe Flanigan, Rachel Luttrell
Revealing mistake: When they are escaping in the beginning of the episode, watch Rodney dial. As he finishes, one of the DHD address panels pops out and falls off.
Dr. Rodney McKay: Did I mention that I know almost everything about almost everything?
Trivia: The show's two hour premier broke the SCI-FI's ratings record by attracting over 4.2 million viewers. It was also the most watched cable program that day.
Question: When the ancients return to Atlantis they are greeted by 2 star general O'Neill but later in that episode and the part 2 episode he only had one star on his uniform. This same thing happened in a SG-1 episode when Dr. Jackson became a prior for the Ori.