Continuity mistake: When the terrorists attack the van at the bridge, shortly after the explosion, you see the terrorists crossing the water in a boat. In the background you can see the van on the bridge with its doors open, shortly after this the terrorists are at the van doors demanding that the police open the van doors!
Factual error: Just before Sean Miller shoots the bookseller he takes the safety catch off the Ak-47. However, he moves the catch two clicks down and then fires the weapon on automatic. This is incorrect. For most modern weapons the safety catch feature goes safe-semi-auto, however the AK safety catch goes safe-auto-semi.
Trivia: As Harrison Ford leaves the naval academy he hesitates and stares across at his would-be assassin, who is hanging around suspiciously on the opposite side of the street. The street name sign under which the man is standing reads 'Hanover Street'. Hanover Street was the first film in which Harrison Ford played the leading role.
Sean Miller: How's the family, Ryan? Nearly lost 'em, didn't you? It's easy to get at them. You should look after your family better, you know? Are you there?
Jack Ryan: Yeah.
Sean Miller: I understand your little girl's feeling better, eh? Lost her spleen though, eh? Pity, that. Make it a mighty tough on her to fight off infection, eh Jacky?
Jack Ryan: You sick son of a bitch.