The SWAT Officers who deliver the secure phone at the beginning of the film in the bank robbery scene were actual LAPD SWAT Officers who were on scene as technical advisors for the film, and got to put on their uniforms and do it "for fun".
The bank used at the beginning of the film was an abandoned building scheduled to be torn down, so the film crew was allowed to shoot at it, tear it apart and do whatever they wanted to. They also had to get over 500 signatures from residents and businesses for permission to fly the helicopters at low altitudes during the SWAT team insertion.
EASTER EGG: Go to Deleted Scenes from Special Features. When "Hondo reviews files at home" is highlighted, press left twice, and up once. This will highlight Street's shield. You can see the footage from the real high speed chase that happened on the 6th street bridge while filming.
Colin Farrell wanted to perform a stunt as his character, in the scene where the S.W.A.T. team rappels down from a helicopter. His request was refused, as a concern for the star's safety. Farrell's stunt double proceeded to break his ankle on the first take of the stunt.
The ending scene was filmed at a California State Prison in the desert, and during filming, the prison guards had a bad situation with the inmates, and had to go into lockdown, with half of the film crew inside the front gates, and half of them outside. Three hours later, when the lockdown ended, filming resumed.
The 6th Street Bridge had been closed for filming, and a high speed chase involving a stolen vehicle actually drove through as the cast was rehearsing the scene. At the time, the Learjet was parked on the bridge in such a way that there was just barely enough room for a mid-sized car to fit through, with a few inches of clearance on each side. At first, when the crew was told by Security that a chase was headed their way, they thought it was a joke until they noticed LAPD and news helicopters above them. The crew tried to include the footage they got later, from the choppers, into the movie, but it didn't work too well.
In the scene where they were using facial recognition to identify Alex, ID photos of the entire crew were used, as the high speed shuffling of faces on the monitor. On DVD, if you step through that sequence frame by frame, you can see almost every member of the film crew. All photos, in that sequence, were taken by Dave Nico, SWAT's Assistant Coordinator (his photo does not appear).
The opening sequence at the bank, is loosely based on the 1997 North Hollywood Shootout. Several radio calls (e.g. "There's nothing we have that can stop them!") are also taken verbatim from the recording of the 1997 incident.
As Alex Montel (Olivier Martinez) is being handcuffed by Jim Street (Colin Farrell), he is seen face down over Alex Trebek's star on the Hollywood Walk of Fame. Alex Trebek also provides the (uncredited) newscast voice-over during this shot.
EASTER EGG: On the DVD go to the second page of the Special Features, select "6th street bridge" press right twice and down twice. This will highlight Samuel L Jacksons's cap. Press Ok or equivalent and you will be taken to the SWAT team and crew playing golf.
Most of the SWAT members, including Street, are shown to be P3's, or Police Officer III, rank. That is shown by the 2 stripe chevron worn on their uniform shirts. The Police Officer III rank is a designation given to Police Officers who have passed a test and is considered to be a senior police officer rank. P3's are usually training officers, and can even stand in place for Sergeants, as needed.
For the limo scene, after the team escapes the sewer, the film crew had called various actors, trying to get someone to sit in the limo for a cameo, but they chose to have actors as high school kids, when nobody wanted to come on scene, in the middle of the night, to do a cameo.
LL Cool J's character, Deacon Kay, relays what he would do if he had huge amounts of money that the Olivier Martinez's villain offers. He states that he would hire Halle Berry as his yoga instructor. He says this within earshot of Olivier Martinez, who would marry Halle in 2013.
Colin Farrell, Samuel L. Jackson, and Jeremy Renner played in Marvel Comics based movies. Colin playe Bullseye in Daredevil (2003), just a few months before S.W.A.T. While Samuel and Jeremy played the heroic characters S.H.I.E.L.D. Director Nick Fury, and archer Hawkeye, respectively, in the Marvel Cinematic Universe. In both his roles as Hondo, and as Fury, Jackson took roles that were originally scripted as Caucasian characters.
The opening scene with the bank robbery, was a real-life event. It took place at the Bank of America, at the corner of Archwood Street and Laurel Canyon Boulevard. The robbery took place on February 28, 1997.
The Ambassador Hotel, a Hollywood landmark built in the 1920s (and the location of Robert F. Kennedy's assassination), plays itself in the film. Closed in the late-'80s, it has since been only used for location filming and police training. Police have been allowed to train there, free of charge. Before S.W.A.T. (2003), That Thing You Do! (1996) was the first movie to use it as a film location. Currently, the building is owned by the Los Angeles Unified School District, who has plans to tear it down, and build a school.
The Polish hostage, played by David St. James, plays a man paranoid of robot aliens. Later, St. James goes on to play a NASA scientist, in Transformers: Dark of the Moon (2011), working with alien robots.
Officer Sanchez is stated to be in Metro Division for many years but never making SWAT. Metro, or Metropolitan Division, is an elite division of LAPD, containing many specialized units such as the Special Investigation Section (SIS). Metro is not a geographical division like the other stations, but a division for special units that serve all of Los Angeles. SWAT is part of the Metro Division. So Sanchez is already in a special division, just not part of SWAT. Contrast that with Deek, who is a regular patrol officer in Southwest Division, covering only that section of Los Angeles.
With his salary from this film, Jeremy Renner subsequently bought a dilapidated house with a friend that they restored and lived in for awhile. Renner said that they made a fairly significant profit when they sold the house much later.
The song "Samuel Jackson" by Hot Action Cop - which features during the film, and over the closing credits - incorporates a vocal rendition of the original SWAT theme (the same part that is sung by the SWAT team members in the diner).
Dr. Pepper cans are seen in at least three scenes. The first is when Street is cleaning the guns, the second is when Boxer opens the can before his pager goes off. The third is when the Sheriff discovers who Alex really is.
The trivia items below may give away important plot points.
When a location was being picked for the plane escape, one consideration was closing I-405, or a stretch of another highway, on which to land a Learjet, but that was "out of their reach", so they shut down the 6th Street Bridge, from six p.m. to five a.m., every night for filming, and used CGI effects for the plane's approach. The scene with the aircraft taking off, was actually done, with an aircraft equipped with a V8 engine, so they could drive it down the bridge.
Colin Farrell and Jeremy Renner appear as former partners turned enemies. Farrell appeared as Bullseye in Daredevil (2003), who, in the comics, becomes the Dark Avenger of Hawkeye. Renner would later go on to portray Hawkeye in the Marvel Cinematic Universe.