Examples of Factual Errors in Fiction
For any fiction genre:
Using an incorrect date for an actual event, or an incorrect name for an actual person.
Incorrect nomenclature: calling an F-16 a cargo jet, referring to an M16 as a pistol, calling the 82 Airborne the Screaming Eagles (that’s the 101st), etc.
Historical fiction: To be credible, the story must fit into the period depicted by the author. So, referring to President Lincoln as if he were still alive in late 1865, or referring to a state before it existed would be a factual error.
SciFi: it’s credible to depict faster-than-light travel, but not to say that light travels at 186,000 miles per hour (it’s miles per second).