Michael Keaton is seen wearing a Pittsburgh Pirates hat in the movie. Keaton is from Pittsburgh, and an avid Pirates fan.
Christopher Reeve and Michael Keaton portrayed DC comic book superheroes on the big screen: Reeve played Superman in Superman (1978), Superman II (1980), Superman III (1983), and Superman IV: The Quest for Peace (1987); and Michael Keaton played Batman in Batman (1989) and Batman Returns (1992). And, in the upcoming Flash movie.
Inspired by the real-life relationship between James Carville and Mary Mataline. Unlike their film counterparts, Carville is a Democrat who worked for Bill Clinton's campaign, while Matalin is a conservative Republican who worked for George H.W. Bush.