Factual error: The pilot is flying from the left-hand seat. Helos are flown from the right side. (01:23:00 - 01:25:00)
Factual error: TV reporters said "home invasions" and mentioned trying to find the people who were responsible for the "70 robberies." Lance (in prison), was talking to a woman who was going to write a book and told her he got "twelve years" for "fifteen counts of robbery and vandalism." The crime Lance and the rest of the group were committing fits the legal definition of "burglary" in Illinois (basically, entering an occupied structure with the intent to commit a felony or theft inside; the structure does not have to be occupied at the time of the act). Because there happened to be someone at home during their last (intended) "burglary", this offense would be classified as a "robbery."
Factual error: The car's cigarette lighter pops out (ready to use), and Bo exits the vehicle carrying the still-lit lighter, glowing like a flashlight. Nearly a minute and a half later, the cigarette lighter is still fully glowing - but car cigarette lighters only stay lit for a much shorter period of time. (01:20:00 - 01:21:23)
Factual error: The Mahindra tractor in the film is newer than the 1980's setting. The tractor appears to be a '90's model. Mahindra tractors were not in the American market in the 1980's. Also, the "plow" used in the plowing scene was actually a "middle buster" plow. This plow would not be used at this stage or soil preparation. A turning plow would have been more accurate.
Factual error: Trevor was driving ECTO-1 at over 60 mph. Podcast was driving the remote car and it was pulling away from ECTO-1. There is no way that the remote car could be going faster than ECTO-1, unless it was souped up, which it didn't appear to be when looking at it.
Suggested correction: There are plenty of RC cars on the market right now that anyone could buy that are capable of going 60+ MPH (the fastest can hit about 100 MPH). And if you take them apart, they don't look "souped up" at all. They just look like regular RC cars inside. Components don't have to look fancy to function fancily. You also have to account for the fact that the movie is highly fantastical, so there's no telling what kind of technology the RC car uses... for all we know, it could be nuclear-powered like the proton packs.
Factual error: Real-life Martina Franca is a town in Puglia, at the "heel of the Italian boot." The town shown in the film is the famous San Gimignano in Tuscany. And when Holly "defects" in order to go to the Hill of Tara, her departure point, as seen on Foaly's observation monitor, is the real-life location of San Gimignano. (00:35:50)
Factual error: The calendar at the end shows 3rd September but the radio announcement is of the declaration of war which in the UK was 1st September.
Factual error: Medical doctors in the U.S. do not simultaneously use "Dr" as a prefix and "M.D." as a suffix, but the business card Grace had on her refrigerator for her hepatologist had "Dr. Perkins, MD" on it. The business card should have included his first and last name followed by "MD" (or "M.D."). Dr. Jane Doe, for example, would be used by a person with a Ph.D. (Doctor of Philosophy). The business card also lacked a phone number and office address. (00:06:19)