During the shoot, there was a script revision which changed the role of the 'Universe' in the movie -- the two Arquillians at the restaurant were originally warring species, who would exchange the galaxy to end a war which Edgar Bug wanted to keep going. Fortunately, some creative tricks could be used to avoid having to re-shoot several scenes. For instance, the Arquillian restaurant dialogue was originally in English, but were redubbed in post-production in an alien language that could be subtitled with a new explanation. Similarly, new expository lines were written for Frank the Pug, whose scenes had to go through post-production anyway. Director Barry Sonnenfeld could be heard on the DVD bonus material jokingly advising fellow directors to include a talking dog into every movie, which makes it easy to change the plot while filming.
When K reveals there are about 1500 aliens on Earth and most of them are on Manhattan just trying to make a living, James asks "Cab drivers?". This is a reference to writer Douglas Adams's 'The Hitchhiker's Guide to the Galaxy' novels, particularly the final novel 'So Long, and Thanks for All the Fish', where archivist Ford Prefect's entry in the Guide hints that driving a cab is a good way to make a living for aliens visiting New York.
Through an apparent lab error, at least portions of the release prints used in the U.S. were not hard matted for spherical widescreen projection. This meant that if the projectionist did not properly frame the projected image, the audience would be able to see lens shades, microphones and other things not normally visible in the frame area.
According to production designer Bo Welch, the MiB headquarters was designed to resemble a 1960s airport (the examination room of the MIB was particularly based on the TWA terminal at JFK International Airport). He used the 1960s theme because that was when MiB started up (as well as the decade of the space craze), and the airport design was because MiB's extraterrestrial affairs include their arrival and settlement to Earth, which airports assist in.
To make them into credible flying saucers, the CG renditions of the towers at Flushing Meadows, Corona Park, where the finale takes place, are substantially different from the actual buildings. Primarily, there are actually three structures of varying height, not two as shown in the film. Additionally, the saucer dish of the shortest tower intersects with the poles of the taller ones, and the dish of the mid-sized tower intersects with the pole of the largest one. Therefore, there is really only one complete saucer - on top of the tallest building. Moreover, the dish atop the highest tower is double the thickness of the shorter tower, not equal as depicted in the film.
Originally there were going to be two huge alien spaceships looming over Earth: an Arquillian ship and a Baltian ship, with representatives of both species staking claim of the galaxy. Mr. Rosenberg (the "little dude in the big dude's head") was a Baltian (confirmed by the novelization of the film), while the tall alien (Carel Struycken) he met at the restaurant was an Arquillian (and is so listed in the end credits). After some choice editing and rewriting, Rosenberg became an Arquillian.
Yasushi Nirasawa worked on some designs for the Edgar Bug which ultimately went unused. One of his takes on the Edgar Bug was a creature more humanoid in form, with two heads and very long arms which resembled the forelegs of a praying mantis.
Actor Vincent D'Onofrio researched his role as Edgar by watching a lot of bug documentaries. In order to achieve his character's distinctive walk, he put on knee braces so he couldn't bend his legs, and taped up his ankles.
When Edwards (Will Smith) jumps from the overpass onto the tour bus, he jumps from Pershing Square Bridge, the same location where Robert Neville (also Smith) is attacked by the demon dogs after the sun goes down in I Am Legend.
The double-action revolver carried by the tow-truck driver and later by Edgar in the morgue scene is a Ruger Super Redhawk .44 Magnum, which is available in two barrel lengths. This one has a 9-1/2" barrel and weighs 58 ounces (i.e., a little over 3-1/2 pounds) empty.
During pre-production, Barry Sonnenfeld changed a lot of the film's aesthetic: "I started out saying aliens shouldn't be what humans perceive them to be. Why do they need eyes? So Rick did these great designs, and I'd say, 'That's great - but how do we know where he's looking?' I ended up where everyone else did, only I took three months."
Lowell Cunningham's comic 'The Men in Black' was much darker and dryer than the family-oriented sci-fi comedy this film adaptation was. In the comics, the MiB survey not only extraterrestrial activity, but paranormal and supernatural activity on earth as well. They are allowed to maintain secrecy by any means necessary (including elimination); they also had a secret agenda: to manipulate and reshape the world in their own image by keeping the supernatural hidden. The comic's basic plot was of MiB Agent X going on the run and trying to keep from getting eliminated.
Producers Walter F. Parkes and Laurie MacDonald originally wanted Barry Sonnenfeld to direct, because he had helmed the darkly humorous Addams Family movies. However, Soonenfeld was making Get Shorty at the time, so Les Mayfield was going to replace him, because the positive reception to his film Miracle on 34th Street. The producers saw that film later and decided he was inappropriate for a sci-fi comedy, so they decided to wait until Sonnenfeld was available.
Tommy Lee Jones only accepted the role of K after Steven Spielberg promised the script would improve. He had been disappointed with the first draft, which he felt did not capture the tone of the comic.
The film was going to be set in underground bases/locations, including Kansas, Washington DC and Nevada, but Barry Sonnenfeld made New York the film's main Earth location. He thought it was more believable that aliens could hide out in a global capital (safety in crowds), and thought New Yorkers would be more tolerant of people who behaved oddly (who were in fact aliens in disguise). He also felt much of the city structures resembled flying saucers and rocket ships, which could be REAL spacecraft and other hidden alien technology.
Rick Baker claims his work on this film was his most complex to date, as he had to have approval on his alien designs from both director Barry Sonnenfeld and producer Steven Spielberg: "It was like, 'Steven likes the head on this one and Barry really likes the body on this one, so why don't you do a mix and match?' And I'd say, because it wouldn't make any sense."
When K is in the diner for the first time with James Edwards, the scene starts with the punchline of a joke that K is telling; the rest of the joke is likely some variation on the following: A farmer decided to go into town to see a movie along with his pet rooster. Noticing that no animals were allowed inside the cinema, he smuggled the rooster into the theater in his front overall pocket and unzipped it once the lights had dimmed and the movie had started so the rooster could see. The woman sitting next to him eventually noticed, and nudged her husband. "I think this man is a pervert. He's got his thing out." Her husband replies, "So? It's nothing you haven't seen before." to which she says "But honey, this one's eating my popcorn!"
Much of the MIB traits and characteristics are in-keeping with established lore of Men in Black. For example, supposed encounters with MIBs, witnesses report they use outdated jokes and vernacular and that their dress and vehicle seem to be dated as well. In the Chinese restaurant, Agent Kay tells Edwards "Agent Jay", "be there or be square", an expression that's out-of-place for mid 1990's humor.
According to the novelization, J is right to shoot Tiffany, the cardboard cutout on the MIB firing range. She's actually a dangerous alien in disguise, while all of the other aliens around are completely harmless.
After script rewrites looking for a more action oriented ending, the original animatronic Bug was discarded after 8 months of development. The new sequence using a redesigned Bug contain 45 CG shots, at a cost of $100000 each. According to director Barry Sonnenfeld "It was the best $4.5 million we spent".
After Edgar bug kills the Arquillians in the diner he leaves the restaurant and walks down the sidewalk. The camera cuts back to the cat in the restaurant where we hear the cat growl. The cats growl is actually a sound effect from the "zombie" monster in the 1996 PC game Quake.
In the scene where K is searching for his old girlfriend, when the satellite video feed of her appears, it lists coordinates of Latitude of 44.41 N and Longitude of 70.0 West. On a map, those coordinates are in the small town of Readfield, Maine, in the middle of Chimney Road, about 3000 feet Northwest (or so) from the intersection of Chimney Road and Main Street.
The trivia items below may give away important plot points.
The final scene reveals that our universe is seen to exist in a gaming marble, just like the miniature galaxy. Both the scene and concept of the miniature galaxy were was inspired from Douglas Adams's novel 'The Hitchhiker's Guide to the Galaxy', where Ford Prefect tells Arthur Dent he knew of a planet that got used in a game of inter-galactic bar billiards and was potted into a black hole ("only scored 30 points, too").
The appearance of a female with the initial L (Laurel Weaver/Agent L) appears to be in keeping with the main MiB agents (J, K, and L). However, it could also be a reference to the comic hero Superman, an alien who often dealt with females with initials of L (Lois Lane, Lana Lang, Lori Lemaris, etc). Weaver's designation as L is also a clever language joke: the French term 'elle' is used when referring to "she" or "her".
At the end of the film, Agent J reveals to Agent L that Dennis Rodman is an alien. This was changed to Michael Jackson in the German dubbing of the film due to Dennis Rodman not being widely known in Germany. Incidentally, Michael Jackson appears as Agent M in Men in Black II.