The filmmakers were not shy about changing Abagnale's story. To heighten the pain of his parents' divorce, they made him an only child, rather than one of four. To enrich the relationship with his father, they turned his straight-arrow dad into a hustler. They compressed the narrative from five years to three. They doubled the amount of money Abagnale said he stole. They invented an FBI agent who pursued Abagnale around the country early on in his scam and eventually to France, when in fact the lack of a coordinated law enforcement effort allowed Abagnale to avoid detection for years. (The epilogue goes so far as to credit the fictitious FBI agent -- a composite character -- with the career honors won by the real FBI agent who arrested Abagnale but spent little time on the case.)
Said screenwriter Jeff Nathanson, who worked on the script for three years, "Nobody really cares about ... having to know exactly what happened. But it does matter that we stayed true to sort of what we know happened emotionally to him as a kid." Still, Nathanson said, the "focus on what's true and what's not true" is "very hard for me
"Frank's an interesting guy and I consider him a friend, but ... he doesn't really allow people to get to know him all that well," Nathanson said. "I don't know if anyone will ever know the actual truth."