Factual error: It's mentioned that the British and New Zealanders turned the Americans away. This is untrue - the Americans stayed with both for a time until it was decided that they would be safer with the Canadians.
Factual error: In the scene where the Swissair 747 is taking off from Tehran the police cars keep up with the plane until it lifts off. Takeoff speed for a 747 is about 160 mph so the police cars would have been far behind by then. (01:41:40)
Factual error: Error in the Istanbul scene. Ben Affleck is shown entering what looks like the Blue Mosque in Istanbul. We are shown the outside and the courtyard of the Blue Mosque with its distinct blue rooftops. When Ben Affleck is meeting another dude inside, they are inside the building which now serves as a museum and which is known as "Hagia Sophia." (00:48:40)
Continuity mistake: Ben Affleck gets into a 280s Mercedes driven by the Canadian Ambassador. The front screen wipers on the car are original silver chrome style and fit the screen. When they arrive at his house the wipers have now changed to much shorter modern style wipers, are black, and are the very latest frameless style first introduced in the early 2000's by Bosch. (00:54:04)
Factual error: In the final scene where the Swiss Air 747 is taking off, the police cars are travelling right behind the engines of the jet. They would have easily been blown away by the engine. (01:41:15)
Factual error: They play a track "When the Levee Breaks" from a Led Zeppelin album. The hand shows the needle being placed at the next to last track on the album. However, "When the Levee breaks" is the last track on Led Zeppelin IV's second side. (01:18:30)
Factual error: In the beginning of the film, when Agent Mendez is called to CIA Headquarters, as he passes the secretary's desk, the outgoing letter propped against her word processor has two postage stamps affixed (2-cent Navajo necklace & 37-cent US Flag) which were first issued and then reissued by the US Postal Service beginning 2003-04, 23+ years after the hostage event in 1980. (00:14:10)
Continuity mistake: As the actors all gather around the table to begin reading the Argo script aloud to the media, we see a two shot as the C-3PO character takes a seat at the table. In the next shot (a wide shot), we see the C-3PO character standing in the background, preparing to take his seat. (00:39:55)
Factual error: The embassy takeover was November 3rd. A scene in Washington DC described as 69 days later showed Tony Mendez driving around town with yellow/fall like leaves on the trees, something that would not have been true in the middle of January. A similar scene at the end of the movie has Tony Mendez approaching his house in Virginia and a very fall like scene is shown. (00:13:45 - 01:49:00)
Continuity mistake: There is a scene after Tony came up with the idea for the fake movie and presented it to the CIA, where he is looking at papers under a magnifying glass. Tony is holding his cigarette in his left hand under the magnifying glass. The very next shot shows his face, and he suddenly has the cigarette in his mouth. Which he then removes with his right hand. The next shot shows it in his left hand again. (00:25:10)
Factual error: As a newspaper from January of 1980 is displayed, the Rolling Stones song "Little T&A" is played. That song appeared on the "Tattoo You" album, which was not released until Aug. 24, 1981.
Factual error: CIA agent Mendez takes-off from Washington to Tehran, apparently via London because he boarded a British Airways flight, on a twin engine aircraft. Twin engine aircraft flights across the Atlantic were just being introduced by TWA around 1980 and weren't flown by BA until years later, if at all. Also, the BA Boeing 747 depicted had tail colors that were not introduced by the airline until the early 2000s. (00:46:35)
Factual error: The turbans worn in the scenes in Tehran are not the sort worn by Iranian clergy - they are wound incorrectly and are too flat.
Factual error: The interior shots of the Swissair 747 cockpit show a mockup. The window frames as shown are very wide and thick, but the real ones are much thinner. (01:39:55)