Character mistake: When Jimmy explains to the kids of the town where the aliens took their parents, he mentions the origin of the aliens being somewhere in the Orion Star System, 3 million light years away. The Orion system is way closer than that. It is actually less than 1400 light years away from Earth. 3 million light years away would place them further than the Andromeda Galaxy.
Suggested correction: This shouldn't be a character mistake. A genius like Jimmy would know something like this. It's basic astronomy.
That's exactly why it's a character mistake. A character mistake is when a character does or says something that they shouldn't based on who/what they are suppose to be, or something a character wrongly states as fact when they should know better.
Character mistake: The acronym USGS (United States Geological Survey) is stated correctly at the beginning of the film, however, upon arriving at the military outpost, Dr Block says "United States Geological Society", not 'Survey'.
Character mistake: It sounds like the person who called him on the cell is not a secretary but also Cameron Diaz pretending to be a secretary. The same voice. (00:07:12)