California Doubling: Filmed in East St. Louis and St. Louis to keep the budget low. Entire areas were in such a state of neglect — urban fires had severely damaged them only a few years earlier — to the point where sets didn't even have to be built. Four years later, the scene of the Batter Up!Blood Sport (see above) was renovated into a hoity-toity shopping area — visual Mood Dissonance.
Deleted Scene: The film was intended to open with a bank robbery detailing how Snake got captured. There was also an excised sequence about Snake encountering a group of Native American prisoners living on the ground floor of the World Trade Center, who would have attacked Snake as he fled from the building (the sequence also would have set up why they sabotaged the glider later on in the film).
Enforced Method Acting: In some of the shots during the fight scene, Snake's expressions of terror are real. Ox Baker, having never done a film before, got a little too into his role, and poor Kurt Russell really did end up fearing for his life.
Technology Marches On: A monitor displays a 3D wireframe model of NYC as Snake lands his glider in the city. The filmmakers wanted to use an actual computer model, but since technology wasn't there yet at the budget they had, they compromised by building a physical miniature New York, outlining it with reflective tape, and filming the result. This was the budget option.
The studio was not initially keen to hire Kurt Russell as Snake Plissken due to his past work as a Disney kid and tried to counter-pitch director John Carpenter on either Tommy Lee Jones or Charles Bronson (an idea Carpenter shot down on the grounds that Bronson was too old). Other candidates for the role of Snake included Clint Eastwood, Chuck Norris, Nick Nolte, Jeff Bridges and Kris Kristofferson; Nolte and Bridges declined because they just weren't interested and the latter was declined by the studio due to the failure of Heaven's Gate. But Carpenter fought for Russell and he eventually won.
John Carpenter had originally considered a scene where Hauk reveals that the explosive charges in Snake's neck were a hoax intended to coerce Snake into rescuing the President, but decided not to use it. Carpenter did, however, use this plot device in the sequel Escape from L.A..