The spray can that Liev Schreiber uses to cut through the chain link fence, is supposed to be a real-life C.I.A. chemical spray, known as "Ice Piss". When asked if a real can of Ice Piss could be acquired for the scene, the Technical Advisor said, "I don't want to go to prison!"
Phil Alden Robinson changed the villains from Islamic extremists (in the novel) to Neo-Nazis. This was done, because prior to the September 11, 2001 attacks, he did not believe Arab terrorists could plausibly accomplish all that was necessary for the plot to work on film. After 9/11, the production staff had to review how to present the movie to the public.
When Ben Affleck first arrived on the set, he told Director Phil Alden Robinson, "Nice working with you again". Robinson said, "What do you mean 'again'?" Affleck explained that when Robinson was filming the scene in Boston's Fenway Park for Field of Dreams (1989), he and Matt Damon were among the thousands of extras.
The title is paraphrased from a Winston Churchill speech; "Why, you can take the most gallant sailor, the most intrepid airman or the most audacious soldier, put them at a table together, what do you get? The sum of their fears."
Real U. S. Marines, along with two Marine Corps CH-53E Super Stallion helicopters, were used for the sequence of rescuing Fowler from the wrecked motorcade. The mission conducted by the Marines in this scene, is what to expect when executing a TRAP (Tactical Recovery of Aircraft and/or Personnel). TRAP missions are most likely to be assigned to a Marine Expeditionary Unit. All Phil Alden Robinson had to do was point at the overturned limo and say "The President is in that car!"
The nuclear bunker, into which James Cromwell and Morgan Freeman walk, at the beginning of the movie, is a real nuclear bunker. The scene was shot at a real bunker in Carp, Ontario. This bunker was designated as the one, in which members of the Canadian government, including the Prime Minister, would be housed during a nuclear attack. The bunker was in operation from 1961 until the mid 1980s, and was known as the "Diefenbunker", in honor of former Prime Minister John Diefenbaker, who was Prime Minister during its initial construction.
This film is a prequel to the others in the Jack Ryan series. The Harrison Ford films are direct follow-ups to The Hunt for Red October (1990), despite the re-casting of Alec Baldwin's role. Nevertheless, in this film, we see Jack Ryan meet John Clark, something which also happens in Clear and Present Danger (1994). Therefore, this film might be best understood as a reboot of the Jack Ryan franchise.
During the opening, a nuclear bomb is shown being rolled out to be loaded onto an Israeli A-4 Skyhawk. However, the bomb designed for the scene, could not be physically carried by the A-4, so the subsequent scenes of the plane had to have a CGI bomb attached in post-production.
In the scene at the beginning, Ben Affleck's and Lee Garlington's characters are talking about Elena Rhyzkov. Garlington played Dr. Elena Rhyzkov, who was working with Dr. Gunter Janek in Sneakers (1992).
The facility, on which they zoom, in the satellite shot near the beginning of the movie, is the actual Mt. Weather "continuity of government" bunker, which was constructed in the 1950s. The town of Frogtown, Virginia lies just to the west.
Russell Bobbitt, the California Property Master, also plays the Israeli pilot in the opening scene. The prop picture in his fighter plane, is that of real-life daughter Jordan Lynn, and was chosen before he was cast as the pilot.
According to the DVD director's commentary, the brief scene of intimacy between Ben Affleck and Bridget Moynahan, where they are in bed and play footsie, ended up being one of the first scenes shot of the two together.
Dr. Elena Rhyzkov, a character mentioned in an early scene set in the C.I.A. offices, was also a character in Phil Alden Robinson's Sneakers (1992), in which Rhyzkov was played by Lee Garlington, who also appears as Mary Pat Foley in this film.
After having bought the 12-type fission bomb for four hundred dollars from the Arab digger (a nominal sum, for the digger's dead son rather than the "worthless" device), Olson e-mails his contact. On the television in the background, an episode of the BBC television series Antiques Roadshow (1997) is playing. This is a show that tours the UK (and occasionally other parts of the world) assessing and valuing items that the general public have found, just like the digger did, and often surprising people with their value.
The shot of the crippled aircraft carrier, was originally intended to be an establishing shot before the attack. This explains why there is no crew visible, despite the fact that crew and pilots were seen racing for the fighters a few moments before.
The Super Bowl scene takes place in Baltimore. The two teams playing in the game are portrayed by the Toronto Argonauts and the Montreal Alouettes. The Montreal Alouettes used to be known as the Baltimore Stallions of the Canadian Football League. The Baltimore Stallions were part of the failed American expansion of the CFL, and relocated to Montreal in 1996. However, the CFL doesn't recognize Baltimore's franchise history or records as part of Montreal's official team history, but that the Alouettes are a continuation of Montreal's continuing history with the CFL since 1946, with operations being suspended between 1987 until their return in 1996.
The sequence where the aircraft carrier U.S.S. John C. Stennis (CVN-74) is attacked and crippled by Russian Tu-22 Backfire bombers with missiles, is a composite of at least two of Tom Clancy's novels. The overall sequence of a U.S. Navy aircraft carrier being almost sunk by Backfire-launched missiles, is from "Red Storm Rising", though the aircraft carrier in question, was the U.S.S. Nimitz (CVN-68) rather than the Stennis. The Stennis, however, does appear and gets damaged in a later book, "Debt of Honor", although not to the extent shown in this film. (As a side note, "Red Storm Rising" is one of Clancy's few novels not to be set in the Jack Ryan universe).
Morgan Freeman later went on to play Lucius Fox, ally to Batman (Christian Bale) in Christopher Nolan's Dark Knight trilogy. Ben Affleck would later play Batman, a.k.a. Bruce Wayne, in Batman v Superman: Dawn of Justice (2016) and Suicide Squad (2016).
The trivia item below may give away important plot points.
At around 44 minutes into the movie, in a scene with his conspirators, Dressler holds up a cigarette and says "I'm told these things can kill you." At the end of the movie, he is killed by a bomb triggered by his use of the cigarette lighter in his car to light a cigarette.