The scene with Tom Cruise alone in Times Square is not computer enhanced. The production was given unprecedented permission to shut down Times Square for one Sunday. At the time, the news ticker was providing updates on the George W. Bush-Al Gore election. To avoid dating the film, Crowe got permission to change the NASDAQ sign in post-production.
During the Times Square scene, while David is running next to a building with glass walls. If you look very carefully at the next sequence of frames, you can make out a line of people at the window watching the filming of the movie. Cameron Crowe thought about digitally removing them in post-production, but decided it fit the theme of "subtle paranoia" and left them in.
David Aames lives in The Dakota, the famed New York City apartment building where John Lennon lived (and died). The interior was built on a set, and the exterior seen briefly at the start of the film was shot without a permit, as the residents do not allow filming on the premises.
Open Your Eyes (1997) director Alejandro Amenábar said about Cameron Crowe's version of his film: "When I learned, quite some time ago now, that Cameron Crowe was going to write and direct the film based on Open Your Eyes with Tom Cruise in the leading role, I felt honored. Now that I have seen Vanilla Sky, I couldn't be more proud. Cameron has all my respect and admiration. Respect, for having plumbed the deepest meaning of the work. Admiration, for having sought new viewpoints and a fresh approach to the mise-en-scene, giving the film his own unmistakable touch. Vanilla Sky is as true to the original spirit as it is irreverent towards its form, and that makes it a courageous, innovative work. I think I can say that, for me, the projects are like two very special brothers. They have the same concerns, but their personalities are quite different. In other words, they sing the same song but with quite different voices: one likes opera, and the other likes rock and roll."
Penélope Cruz also starred in Open Your Eyes (1997), of which this film is a remake. She played the same character, Sofia, in the earlier film.
Steven Spielberg: A guest at David's birthday party (wearing a Pre-Crime cap from Minority Report (2002)). Spielberg and Tom Cruise were preparing to begin filming "Minority Report" at that time. In a returned favor, Cameron Crowe cameos in that film.
William Mapother: In the night club, David interrupts a conversation that Sofia is having with another man, played by Tom Cruise's cousin.