Factual error: When Smithers (not identified by name in the movie) gives Alex his kit, it includes a fountain pen which shoots a dart filled with Sodium Pentathal. That's supposed to cause a person to do what Alex says. Sodium Pentathal is a form of barbiturate. Barbiturates cause impaired coordination, therefore it's unlikely that Mr. Grin could have flown a helicopter under its effects.
Stormbreaker (2006)
1 factual error - chronological order
Directed by: Geoffrey Sax
Starring: Mickey Rourke, Robbie Coltrane, Stephen Fry, Alex Pettyfer, Damian Lewis, Sarah Bolger, Sophie Okonedo
Continuity mistake: Near the end of the movie, when the helicopter sets down on top of a tall building, the registration mark of the aircraft changes noticeably several times, from G-ORMA to G-ICSG and back again.
Jack Starbright: Is it just me or are those bankers weird?