Cathy and Sally Ryan arrive at the hospital via a "LifeFlight" helicopter. MedEvacs in Maryland are primarily done by the Maryland State Police and there is no "LifeFlight" helicopter anywhere near the state of Maryland.
The announcement also contradicts itself, telling passengers both that the train is for Hatton Cross and that they must change at Acton Town for Hatton Cross. Also, the instruction "all change" means that passengers for ANY other destination must change, and is not used in relation to a specific destination.
When the electrician examines the wiring in Cooley's bookshop he says that it dates from before the First World War. However this is after he has wiped the dust of a junction box which is dated 1917 - 3 years after the start of the war.
Just before he is shot, Jimmy O'Reardon is naked on the bed. As he is being shot, a blanket suddenly covers the lower half of his body. When he falls backwards onto the bed, the blanket also moves as if it is attached with some sort of adhesive.
The two cars accompanying each prison van are identical early-1990s model Vauxhall Cavaliers, yet the wrecked burnt out car to the rear of the prison van after Sean Miller had been freed is an early-1980s Rover.
The keypad light on Jack's alarm doesn't come on until after he's done setting it. A keypad light would be useless after an alarm has been set and would instead need to come on near the beginning of the process.
When the Ryan family are preparing breakfast, Paddy O'Neill is giving a TV interview. As the family watch this on the larger TV, the portable TV is paused with just the image of Paddy, but on cue the portable begins to play the scene as the camera pans the room.
While the Ryan's are escaping from the attic, Sally slips and rolls down the roof, and Jack catches her. In the next scene, it shows her slipping down the roof a second time from a different angle and Jack catching her again.
Tube trains from Aldwych ran only to the next station, Holborn, yet an announcement is heard in the station: "All change at Acton Town for Hatton Cross. Hatton Cross train stopping at Oxford Circus, Piccadilly Circus, Leicester Square, Green Park, Acton Town, Hampstead Heath, Marble Arch, Hounslow East, [inaudible], Hyde Park. All change at Acton Town for Hatton Cross."
Leicester Square, Piccadilly Circus, Green Park, Hyde Park Corner (not "Hyde Park"), Acton Town, Hounslow East, and Hatton Cross stations occur in that order along the Piccadilly Line. The other 12 stations in between, at which all trains stop, should also have been mentioned. Marble Arch and Oxford Circus are on the Central Line, not the Piccadilly, while Hampstead Heath is not on the Underground at all, but was a British Rail station.
Sean Miller is transferred from a prison in Southwark (in London) to the high security unit on the Isle of Wight. This would involve a land journey of 50 miles to the southwest, then a ferry across the Solent. However, the ambush is depicted as occurring at the Middlesbrough moving bridge, 200 miles north of London; and in later dialogue it's said to have been in Kent near the Channel, which would be southeast of London and at least 70 miles from the Isle of Wight ferry routes.
The Ryans are depicted as working and schooling in the Annapolis metro area, yet live in a secluded home sitting on a high cliff overlooking open ocean. Relative to Annapolis, the nearest view of open ocean is nearly 80 miles due east - the entire width of the Chesapeake Penninsula - on the Delaware coast, which is a region characterized by beaches, barrier islands, and state parks.
Lord Holmes says that The Queen has decided to invest Jack Ryan K.C.V.O. (Knight Commander of the [Royal] Victorian Order). The insignia is a neck badge and a breast star. When Lord Holmes shows the insignia to Ryan at his home, it is just a small round silver medal, the insignia of the Royal Victorian Medal (R.V.M.), a very minor award by comparison.
When Dennis Cooley is in the desert begging with the IRA members to go on the mission Sean Miller tosses him a AK47 to test fire, when Dennis cannot operate the gun due to the safety been switched on, Miller takes it back and fires it at Dennis's feet, despite the AK47's powerful rounds no dirt or dust is thrown up from the bullet impacts.
At the beginning of the movie, there is a game of Monopoly being played. The building of houses / hotels breaks the general rules. You have to build evenly, you cannot build a hotel on the Strand, with only two houses on the Trafalgar Square for example. Also the property card for Old Kent Road sits in the bank tray, but a player must own it, as it has a Hotel (and incorrectly another house) on it. The rent for landing on Oxford Street with a hotel is 1275, not 1100 (thats for 4 houses) as called out in the game.
After Sean Miller's highway attack on Caroline and Sally Ryan, Jack Ryan is pacing the floor outside the hospital O-R. His wife is okay, but Sally's condition is unknown at this point. On several occasions, Jack looks out the window, and sees that the local press vultures are swarming all over the place. The goof is, that the reporters and their news vans are camped right on top of the "H" symbol on the hospital heli-pad. Hospital security would never allow this, as the heli-pad must be kept completely clear, in anticipation of future inbound emergency flights.
When the helicopters are approaching the Libya camp, they both have all lights switched on. During the 'fence in' procedure, EVERY unnecessary light is extinguished to reduce visibility. Furthermore, the SAS soldiers tabbing in do so on a dune ridge, sticking out like sore thumbs. Normal procedure is to stay in ravines or other depressed areas.
Jack Ryan is awarded the Knight Commander of the [Royal] Victorian Order, which is only available to British Citizens. The Central Intelligence Agency only recruits US Citizens. Jack could not therefore be knighted by the British. In the book however, an exception was made because he saved a member of the Royal Family, but this is not mentioned in the film.
When the film shows the men running at the Naval Academy, they are wearing Navy sweatshirts, but the very last word they shout in the song is "Marine Corps." This would not be incorrect as up to 1/6 of United States Naval Academy graduates receive commissions as 2nd Lieutenants in the United States Marine Corps.
After the attack on him outside the Naval Academy when Jack Ryan gets in his parked and locked car and drives away the passenger side window is open (due to filming him starting the car). Later the window is seen to be closed.
In the night-vision-goggle scenes in the Ryan home, the windows are extremely bright, indicating that it is brighter outside than inside. NVGs only amplify available light, so at night they would still be darker than the walls. This shows that the scenes were filmed when it was daylight outside and then simply tinted green.
In the night-vision-goggle scenes in the Ryan home, the fire in the fireplace was subdued, not bright. This shows that the scenes simply tinted green, rather than filmed using light-amplification optics.
Towards the end when the terrorists are about to attack the Ryan's house in Maryland they have killed the DSS guards and Maryland State Troopers. A close up of one lying supposedly dead on the ground shows the "dead" guard's eyelids fluttering heavily in an obviousl effort to keep his eyes closed.
In the first courtroom scene, after Jack Ryan is excused by the judge, as soon as Ryan passes by Sean Miller, Miller charges towards him - cursing him. At this moment, Miller voluntarily brings his (free) right arm backwards towards the "handcuffed position" even though the guard was holding onto his other arm.
The goof items below may give away important plot points.
During the attack at Ryan's house, Jack grabs a machine gun from one of the fallen terrorists, yet fails to use it once in defense. Also, when Jack is putting his family in the attic, he does not have the machine gun, but when He, Sally and Cathy make their escape from the attic, he somehow has the machine gun again.
Cathy and Sally are being chased by Sean Miller, and eventually crash. It is obviously filmed on a California freeway, and not in Maryland, as there are several palm trees seen in the background. Plus, looking at the front of the Porsche at the moment of impact, airplanes and the control tower at LAX can be seen to the right.