On July 2nd, they arrive. On July 3rd, they strike. On July 4th, we fight back.Independence Day is a 1996 movie by Roland Emmerich, known in its promotional material as ID4. At its core it is a straightforward Alien Invasion movie with a lot of elements taken from well known sources like War of the Worlds. The archetypical Summer Blockbuster with a large cast of familiar character types, Stuff Blowing Up, fighter jets dogfighting alien craft, Rousing Speeches, Area 51 and is otherwise fairly by-the-book storywise.President Whitmore (Bill Pullman) is the recently elected U.S. President when a massive (one-fourth the size of the moon) spaceship enters the orbit of Earth. Sending out smaller (city-size) ships that scatter across the globe to all the major cities, it doesn't take long before they begin firing their Wave Motion Guns to wipe out entire cities at a time.Humans fight back, with U. S. Marine pilot Steven Hiller (Will Smith) and a computer programmer David Levinson (uh... Jeff Goldblum) pulling together a plan to save the human race.The movie was a smash hit, the most successful film of 1996 and boasting Oscar winning Special Effects. The movie is fondly remembered for having some fun personalities and great action sequences, although the stock characters and generic alien invasion story mean that this opinion is not shared by all. In a large way it started off a new era of the Summer Blockbuster, one that is heavily reliant on special effects and potentially Earth Shattering disasters.The film's success also kicked off a revival of the Disaster Movie in mid-to-late 90s. The influence of this film can be seen even today, with Roland Emmerich himself repeating a similar formula in his later films like Godzilla, The Day After Tomorrow and 2012.Apparently not one, but two, sequels are planned.
Also, Air Force One becomes the de facto capital of the United States for a portion of the movie, as the President oversees the first counterstrike operation from aboard the plane. After that, Area 51 apparently becomes the de facto capital.
Alien Abduction: Russel... or so he claims. The viewer is left to their own devices about whether or not this was entirely a delusion brought on by alcoholism, war trauma, or just being nuts. The novelisation has him see the alien downed by Captain Hiller, and think that's it's not the same as the ones who abducted him. Then he starts to wonder whether other aliens are visiting Earth, or if it even really happened. The same novelization strongly implies that it did happen: inside their bio-suits, the invading aliens look exactly like the ones in Russel's memories.
There was a Marvel comic book that shows several events from the earlier lives of the characters, as a sort of "prequel". Russel is clearly shown to be abducted by the invaders.
America Saves the Day: And how. The entire plan to save the world was conceived by the American characters at Area 51, then broadcast via Morse code to the rest of the world. It's a Justified Trope, though, considering Area 51 is portrayed in the film as harboring a recovered scout craft used by the very alien race invading — implying that the U.S. has had decades to study them for forty years prior. Without that ace up its sleeve, the United States was as helpless as everyone else.
The producers of a British radio spinoff were even given strict instructions not to portray the British as in any way contributing to America's victory. Amusingly, the British radio version hangs a lampshade on this by having one of the characters remark, "What do you want to bet the Americans take all the credit for this?"
The movie itself features a British commander making a similar Take That: "It's about bloody time!" His tone of voice has all the subtext of "Those bloody Yanks are Late to the Partyagain!" Most snarkersinstead interpret the line as playing the trope straight, though.
Anal Probing: Russel attests to having been abducted by aliens. Those who don't believe him crack jokes and ask if he was ever sexually abused on the flying saucer, suggesting this trope.
Apocalypse How: The aliens plan to strip Earth of resources until it counts as a Class 4 Apocalypse.
Everyone makes fun of Russell for believing that he was abducted by aliens. Even after the aliens show up. But it's doubtful that his acquaintances got an opportunity to compare his description of the aliens to the one taken prisoner by Captain Hiller, and in any case he's the town drunk.
Even after the attacks the president refuses to believe in Area 51, though in this regards, his disbelief stems from not being told it existed. As the leader of the nation, he assumed that something of such magnitude wouldn't have been kept from him — especially when aliens began arriving under his watch.
Area 51: Really is the site of a crash-landed flying saucer.
Armor Is Useless: The aliens have biomechanical armor but it doesn't seem to help them very much from being punched out.
The armor might have helped against being shot, if Dr. Okun and the other scientists hadn't cracked it open to vivisect the alien inside. When Major Mitchell and the other soldiers shot it, its armor was open.
Attack Its Weakpoint: The ship's cores — if you can get through the forcefield at least.
Authority Equals Ass Kicking: The president was a fighter pilot and leads a raid against one of the ships, though he doesn't get the final shot to take them down.
Backed by the Pentagon: The producers tried to use this trope, but the Pentagon refused to back a movie whose plot involved Area 51, (because it doesn't exist!). Tellingly, Emmerich noted in one interview (and in the DVD commentary) that the Pentagon bent over backwards to help him get the technical details right until they saw Area 51 mentioned, at which point they pretty much told him that he was on his own.
Bikini Bar: Jasmine is named as a stripper in dialogue, but we only ever see her in one of these.
Bilingual Bonus: Julius Levinson (father of David), who had heretofore not been "on speaking terms with" God, is seen leading a group in the sixteenth benediction of the Shemoneh Esrei near the film's climax.
Bittersweet Ending: The aliens are defeated, but humanity faces an uncertain future.
Black and White Morality: The Earthlings defend their home planet against the evil, heartless galactic locusts from the outer space.
Black Best Friend: A rare inversion. One of the main heroes is black and his white best friend is the wise-cracking comic relief. He fulfills almost every trope related to the black best friend, right down to being the first named character to die.
Steven Hiller:(to crash-surviving alien) *WHAM* Welcome to EARF!
California Doubling: Actually Utah Doubling; most of the movie after the first act was filmed on the Bonneville Salt Flats, near Wendover, UT.
Calling Your Attacks: "Eagle Twenty, Fox Two!" And for good reason. Pilots call "Fox" one through four to indicate firing of different weapons to help avoid friendlies catching one of them. At least that's what these guys say, anyway. Plus it's all dramatic and stuff. In reality, with such a massive fleet of friendlies, this wouldn't be occurring at the outset since the radio feed would get garbled by fifty pilots doing their call while firing a simultaneous opening shot.
Captured Super Entity: At one point, Hiller captures an alien that crashed along with him and drags it to Area 51. The alien's telepathy and bio-mechanical suit make it a formidable force when it's found to still be alive.
Played straight at first when David tries to warn people about the countdown signal in the satellite network. Even his ex-wife refuses to believe him, thinking he's crazy or manipulating her. However, it's finally averted when the President finally hears him out and evacuates the area immediately. People seem to have a hard time taking Russell seriously, even after the aliens show up. Being that he's an alcoholic, it's not surprising.
The president also acts in a condescending way when David's father begins to talk about Area 51, the Roswell Incident, and other alien conspiracies (as he was not told about Area 51 earlier, apparently not even telling the rest of the staff, either, or at least not the Joint Chiefs of Staff, viewing it as better to hold up Plausible Deniability instead.) It turns out, he was right.
Speaking of David's father, he wasn't too sure about David's theories, either. People have a hard time believing each other in this world.
Chekhov's Gun: When Russell gets inside his new fighter jet, he starts screwing around with the controls and accidentally arms a missile to be fired. Guess which missile jams at the end, forcing Russell into a heroic sacrifice?
A quick mention is made that President Whitmore is a former fighter pilot.
Similarly, a television reporter mentions in passing that much of the current information that anybody has is being passed around via amateur radio operators, given the widespread destruction of the government-run infrastructures*
Which is actually a role that amateur radio fills in Real Life
. Guess how the remaining military forces pass word to each other to coordinate their final counter-attack?
Chess Motifs: "And when the countdown reaches zero, then what?" "... checkmate!"
The only man who figures out the alien signal is a countdown happens to have an ex-wife who works for the president, thus getting him access.
Hiller's girlfriend in Los Angeles happens upon the First Lady, so when Hiller finds her, he finds the president's wife (who everyone had pretty much given up for dead).
Hiller, the only known survivor of his unit, is an astronaut wannabe.
Hiller's dogfight with the alien fighter happens to take him near enough to spot Area 51, and his crash put him close to a convoy of refugees he can point in that direction.
A surprisingly large number of civilians amongst those refugees turn out to be former jet-qualified combat pilots.
Death by Cameo: Volker Engel, who was head of the FX unit.
Deflector Shields: At least half of the film is spent trying to figure out how to get around the alien ship's deflector shields with the technology the humans have.
Delayed Explosion: Almost every explosion in the film. The most notable is the explosion of Los Angeles, which apparently moves so slowly that Jasmine has time to grab her son, break open a locked maintenance closet, and even call her dog inside before the explosion reaches her location. It also, miraculously, does not fill the open closet with fire and debris. Nor does it suck the oxygen out of the tiny space, despite the fact the "sucking oxygen" would be the primary cause of the fire shooting through the tunnel.
Both issues are mentioned in the novelization: it spends a whole paragraph describing the Mind Screw effect of seeing an inescapable wall of fire slowly advancing towards you, and another paragraph to explain why Jasmine, Dylan and Boomer weren't deep-fried contrary to all those who hid in cellars (though the explanation is a bit shaky).
Deus Ex Nukina: A particularly egregious example. You can destroy the unshielded atmospheric city destroyers and fighters, but the aliens have billions of reserves on board a super mothership in orbit. You have exactly one transorbit Space Fighter; the enemy undoubtedly has thousands just like it which they are better at flying than you. Fortunately it's already going to the mothership to enable the main attack. So you load a single "tactical nuclear missile" that apparently has many times the yield required to, oh, mass-scatter Ceres.
Even Captain Hiller and David Levinson weren't expecting this to happen; the looks on their faces when the mothership blew up in a spectacular Michael Bay fashion is telling. The nuke was meant to cripple the mothership to buy time, not to destroy the whole shebang.
Does This Remind You of Anything?: When Jimmy bends down on the floor to retrieve a wedding ring dropped by Hiller, another soldier passing by thinks he's proposing to his best friend. The other guy helpfully leaves immediately, not wanting to spoil the moment.
Earth Is A Battlefield: Featuring some pretty impressive set pieces when the humans fight over recognizable land marks.
Earth Is the Center of the Universe: Not completely straight, but somehow the Earthlings managed to stop the alien advance when they've stripped God knows how many planets before them.
Easily Thwarted Alien Invasion: It takes a simple computer virus (and, y'know, a large nuclear warhead) to take down spaceships 1/4th the size of the moon and kill millions of aliens. Gotta love that universal Operating System!
Also a nice piece of Fridge Brilliance. They stated they'd been studying the craft since it crashed in the 1940s, which is roughly the same time operating systems began being designed. Whether or not it was intentional, who can say, but if it was, it's pretty clever.
Emergency Presidential Address: The President delivers an address to urge caution to the public as the alien ships enter the Earth's atmosphere and approach major cities. This is later followed by his "We will not go quietly into the night" speech once the aliens plans are revealed.
Enemy Mine: Israeli, Egyptian, Iraqi and English airforces are shown working alongside each other during the scene where the global counter-offensive is planned, seemingly having agreed to a mutual detente in the face of the alien threat.
Enforced Method Acting: The scene in which Captain Hiller drags the unconscious alien across the desert was filmed on the salt flats near Great Salt Lake in Utah. Great Salt Lake is home to brine shrimp. When they die, the bodies sink to the bottom of the lake (which isn't very deep) and decompose. When the wind kicks up just right, the bottom mud is disturbed and the smell of millions of decaying brine shrimp can be very very bad. Apparently, nobody warned Will Smith. (Watching the film, you assume his improvised line "... AND WHAT THE HELL IS THAT SMELL!?!" refers to the alien.)
Eureka Moment: David's idea to create a computer virus, coming from a simple reminder by his father to take care of himself lest he catch cold.
Every Helicopter Is A Huey: Though most of the aircraft used are period- and setting-appropriate, a Huey still shows up to escort the doomed S-64 Skycrane 'Welcome Wagon'. It explodes moments later.
Didn't Captain Hiller go looking for his family in a Huey?
Everyone Knows Morse: Except aliens apparently. Although they seemed to break the code pretty quick: first thing they did after the message was to send a Wave Motion Gun to Area 51.
Executive Meddling: A deleted scene early in the movie had David explaining exactly how our satellites were being hijacked by the aliens. At the end of the scene, Harvey Fierstein's character planted an (ad-libbed) kiss on David. Ironically, it was Roland Emmerich himself who decided to cut the scene, lest he incur the wrath of the MPAA. And the kiss in question was at best a platonic kiss, so it wasn't even that close to potentially upsetting the MPAA, especially seeing how another thing that Fierstein was in got away with a similar male-male kiss without it being censored.
Eye Awaken: When the alien is being removed from its bio-mechanical suit. Major Mitchell later puts a few more bullets in it until it finally gives out a death cry, obviously aware of the trope.
Five Rounds Rapid: An initial assault with conventional weapons ends in a massacre as the Deflector Shield prevents their weapons from piercing the ships. However, once the forcefields are dealt with, they are susceptible to conventional weapons in their weak spot.
Flying Saucer: Played perfectly straight. And for once, actually scary instead of cheesy.
Four Star Badass: General Grey, as contrast to the mousy, ass-covering Secretary of Defense.
Genre Savvy: The characters figure out what the Deflector Shield does just from being aware of them from science fiction. Hiller declares "they must have some kind of protective shield over the hull". Yes, he picked the term "shield" which matches the sci-fi standard, but there's easily enough context for the non-savvy to understand just fine.
Guilt Free Extermination War: The aliens, in keeping with their Horde of Alien Locusts nature, have no issues whipping out entire cities full of people. Humanity has no issues returning the favor for the alien mother ship.
Hemisphere Bias: Pretty much anything South of the Equator isn't worth concern. Though we get to see crashed UFOs in Sydney and right against Mount Kilimanjaro in Tanzania.
Heroic BSOD: Not quite as severe as normal uses of this trope, but it was made quite clear that Jeff Goldblum's character was not too happy about the circumstances of what happened, eventually causing him to lash out, even litter the whole place quite violently before his dad inadvertently gives him an idea on how to defeat the aliens.
The President has one, lamenting of all the death and destruction caused by his indecision to prepare if the aliens indeed turned out to be hostile.
The President: We could have evacuated the cities hours ago
First, the aliens' signal, that they used to synchronize their attack on the planet provided humans with a way to interface and access their systems (it's stated in the expanded edition that the same frequency is used for their communications) using a Mac of all things.
Second, the "Hammer". This is a nice one: If you look a at the L.A. destruction scene, you'll see that the beam turns into a chain-reaction/explosion the moment it hits solid matter, and just keeps going until there's no significant obstacle left. Therefore, the denser the target, the worse the explosion (like the Mothership from Command & Conquer 3, which was inspired by this movie), making it perfect for leveling cities. When Russell crashed his plane into the generator, he did it at the very moment the beam started, and at the very "tip" of the gun, therefore setting off the chain reaction inside the alien's ship (which is likely to be just as densely packed as a city, if not more so).
I Come in Peace: Used straight and subverted. The military sends a chopper to one of the huge spaceships with a lit sign displaying greetings in all the languages of the world, and civilians in every major city hold up signs of greetings to said ships. The chopper gets blown out of the sky, and the cities (and associated welcoming parties) get cratered, with very little discussion. Later on, one of the aliens, through Dr. Okun, says, "No peace."
If I Do Not Return: When Casse realises he has the only missile left and it's jammed, he says, "Tell my kids... I love them very much," and flies his plane into the alien ship's weak point.
With most of the world's major population centers blown up and massive chunks of alien debris crushing landmasses and plunging into the ocean (no doubt creating tidal waves), the world does not look positive in the wake of the attack. Then again, since the alternative was total annihilation, there's only so much room to complain.
Not only that, but at least in the case of America, most of the government has been destroyed. The vice president and Congress were destroyed during the initial attack, leaving only the president and the military in charge. And yet the president still decided to join the fight even though he's practically the dictator of the US by this point. Considering similar attacks were carried out all over the world, there are probably few world leaders left.
In Working Order: The crashed alien ship from Roswell still works. To be fair, though, they have quite obviously patched huge sections of the hull with Earth-made metal plates, and they've had decades to work on it.
"Checkmate" takes this to ridiculously lampshaded lengths.
And the first lady lovingly calling her husband "Liar."
Israelis with Infrared Missiles: The Israeli military appears in a brief scene and is more than capable of taking out the alien ship in its part of the world. It's also an Enemy Mine scene as it shows they have set up camp inside Iraq alongside British and Iraqi forces.
It Has Been an Honor: Hiller and David have a moment of this at the end of the film when it appears they're not going to survive bombing the alien mothership.
Meaningful Name: Russ T. Casse. (That would be 'Rusty Case' if you didn't know).
Missing Mom: David Levinson. The Casse kids. The President's daughter, presumably, after the events of the movie.
Mobile Suit Human: Not that the aliens are trying to pass for human, but they turn out to be much smaller and possibly weaker inside their suits.
Mood Whiplash: Hiller's line that he's always dreamed of flying in space accompanied with majestic music and the image of the craft flying triumphantly away from Earth... only for the music to suddenly turn dark and ominous as the camera pans to show them heading towards the Mothership.
Money Shot: The alien ship blasting the White House is the emblematic shot of the movie. After that, it's the shadows falling over major landmarks, and their destruction that was the basis of the trailers.
Monumental Damage: The trailers spoiled this one big-time. The first thing you see is the decapitated head of the Statue of Liberty, after the alien attack.
When the President orders his men in the final battle to "Plow the Road". Although, for F/A-18s, that was actually quite insufficient Dakka. The Vulcan Cannons carried by American fighter jets fire at a rate of about 6,000 rounds per minute in Real Life.
And officially an F/A-18 carries 578 rounds for the bun mentioned above which would mean a far less spectacular "Road Plowing" moment as they would run out of bullets after roughly 5.78 seconds...
This troper just watched that scene, and the covering fighters fire a roughly 6-second burst.
Also, we only see the tracer rounds, which are generally every fifth round. Rounds without tracer additives are nigh-invisible.
No Endor Holocaust: Dozens of ships that size hitting the ground would throw up enough dust to blot out the sun. And that's not even considering blowing up something as big as the mother ship in Earth's orbit like that.
The novelization mitigates a bit by putting the Moon between the Earth and the mothership. This makes sense if you consider that something that big would have to have a huge angular velocity to maintain Low Earth Orbit. However, the movie shows an enormous amount of debris racing the delivery fighter back into the atmosphere, and later burning as "fireworks" overhead. If it was actually out beyond the moon when it detonated, the number, implied velocity (a good chunk of the speed of light) and size of those fragments would have been a rather incredible bombardment all on their own.
Nuclear Option: Nuclear weapons are used only once, over a city that's about to fall victim to one of the leviathans, and after significant consideration (primarily over the fact that, whether it works or not, the city is about to get razed to the ground anyway). When the first one doesn't work (read: didn't even get through the target's shields), the rest are immediately called off.
Darker and Edgier in the novelization: this is only briefly mentioned in the movie, but not only is Houston still completely intact at the time of the attack, it hasn't been fully evacuated yet.
Obstructive Bureaucrat: Secretary of Defense Albert Nimziki. Before he became the Secretary of Defense job he was the CIA Director. They had evidence of a hostile alien race, they KNEW what they were capable of, and yet they DIDN'T. TELL. THE GOVERNMENT. This results in the initial counterattack against the aliens being utterly annihilated due to the shields and the US losing hundreds of pilots that could have been more useful if they actually had a way to beat them. The guy eventually tries to talk Whitmore out of attacking the aliens before the end battle, claiming it would be a mistake. Whitmore replies:
It's hard to read expressions on an alien face but it's easy to imagine that's what it was thinking when it found itself staring at a countdown on a nuclear missile that just ticked to zero...
These are Harvey Fierstein's character's last words.
Plausible Deniability: Apparently, the Secretary of Defense who kept the President in the dark even went as far as to keep most of the cabinet in the dark about the existence of Area 51 as well, going by General Grey's reaction to learning this.
Whitmore: Where does all this come from? How do you get funding for this? Julius: You don't actually think they'd spend $20,000 on a hammer, $30,000 on a toilet seat, do you?
Power Armor: Bio-Mechanical in nature, and offers little protection from a punch to the face (which doesn't actually line up with the real head), but with several built-in weapons and decent protection from bullets.
Russel Casse, before he proceeds to shove his F/A-18 up the alien ship's ass and completely annihilate it in a glorious (and, for him, quite satisfying) Heroic Sacrifice.
The President moments prior: "Alright, boys, let's give Mr. Casse some cover. GENTLEMEN! LET'S PLOWTHE ROAD!"
Deep in the mothership and not expecting to get out, Hiller makes a V-sign to the alien in charge of the hangar, shouts "PEACE!" and fires the nuke. And just beforehand, David activates a special option in his virus causing all the alien display screens to show an animated laughing skull and crossbones, complete with demonic-sounding digital laughter.
After the captured alien launches a mental assault on Whitmore and shows him their plans, we get this:
Grey: Is that glass bulletproof? Mitchell: No sir. (all observing military personnel pull out handguns and open fire)
Product Placement: The best-known example is Jeff Goldblum using a PowerBook 5300 (ironically considered even by die-hard Apple fanboys to be one of the worst Macs ever made) to hack into the alien ship.
Random Smoking Scene: Will Smith's character and his comrade both take cigars along with them when they plan to defeat the aliens for once and for all. And they do smoke them after all the aliens are dead, because what better way of celebrating surviving an alien attack than doubling your chances of getting cancer!
They didn't think they would live, so smoking a cigar isn't that big of a deal.
Rousing Speech: "We will not go quietly into the night. We will not vanish, without a fight. We're going to live on. We're going to survive. Today... we celebrate... our Independence Day!"
Rule of Perception: Steven and later Jasmine walk out onto their front lawn with a view over Los Angeles and don't notice the alien ship hovering silently over the city until the camera shows it.
Scenery Gorn: This film revels in the wholesale destruction of the populated centres of the world. (Emmerich returned to make similarly spectacular carnage in The Day After Tomorrow and 2012.) Love of this trope must be the reason that a movie which features the destruction of the White House is shown on American television every year on the Fourth of July.
Screw the Rules, I Make Them!: President Whitmore, finally fed up with Secretary of Defense Nimzicki tells him he's fired, to which Nimzicki grumbles "He can't do that," to which the President's assistant notes that he just did anyway.
Schizo Tech: For the aliens. They have the space travel, laser beams, indestructible forcefields... but their computer security technology is so primitive a guy with a laptop can hack it; they didn't even think about a the possibility of a security breach, even though they were interfacing with the Earth's satellite network. It wouldn't be the first time an alien race of invaders had some technological deficiency that lead to them being defeated (it goes all the way back to War of the Worlds) but this one is particularly egregious.
Semper Fi: Marines have a strong presence in the films cast. Will Smith is a cigar chomping Marine Corps F-18 pilot. William Grey, the President's most trusted right hand man throughout the film, is a Marine Corps General.
Shell-Shocked Veteran: The news report on Russell claims he got this as a result of being a fighter-pilot in Vietnam, but he claims its from his abduction.
To Jurassic Park; Jeff Goldblum's character says, "Must go faster. Must go faster. Go, go, go, go, go, go, go, go!" in the same way as he does in one scene in Jurassic Park. Exactly the same way, in fact: the audio was cut directly from Jurassic Park and pasted into this movie.
There are also shout-outs and Easter Eggs to classic sci-fi shows and films dating all the way back to the 1940s.
The strategy to defeat the aliens mirrors the defeat of the aliens in War of the Worlds, with a different interpretation of the word "virus".
3001: The Final Odyssey (which came out the year after ID4; presumably Clarke had decided on or even penned the ending before ID4 came out) has the heroes dispatch the aliens with the exact same strategy. Arthur C. Clarke writes in the ending notes that he doesn't know "whether to congratulate them for their one stroke of originality or accuse them of retroactive plagiarism". (not exact quote)
David's Mac boots up with a picture of HAL-9000 and the greeting "Good Morning, Dave."
Smart People Play Chess: Julius and David Levinson are shown playing chess together early on, with David winning easily. He spends much of the rest of the movie talking in Chess Motifs.
Some Kind of Force Field: When the first air-to-air missiles reveal a invisible barrier surrounding the big flying saucer, Hiller declares, "They must have some kind of protective shield over the hull!"
Sorting Algorithm of Mortality: The characters who got killed were the stereotypically gay boss, the dumb stripper (a case of Too Dumb to Live), the First Lady who didn't get out in time (a sympathetic character to give the impression that Anyone Can Die), and the alcoholic father (seems like the alcoholic made a heroic sacrifice of redemption so...).
Sound to Screen Adaptation: Inverted with Independence Day UK, a BBC radio drama based on the movie, but set in the UK with original characters. The one stipulation Fox placed on the BBC was that the Brits couldn't substantially contribute to the Americans' victory. This leads to one character muttering, "I bet the Yanks are going to take all the credit!"
As usual, most of Jeff Goldblum's dialogue was improv.
And Harvey Fierstein's "Oh, my God. I gotta call my brother, my housekeeper, my lawyer. Nah, forget my lawyer..." was ad-libbed, although it was original "nah, fuck my lawyer," and then dubbed over (rather obviously).
Similarly, Fierstein's character's planted kiss on Goldbloom's character was ad-libbed by Fierstein. Of course, it ended up cut in the theatrical cut, but restored in the Special Edition.
President Whitman's statement of "Today we celebrate our Independence Day!" was ad-libbed by the actor.
Will Smith's "AND WHAT THE HELL IS THAT SMELL?!" line while ranting about having to drag an unconscious alien through the desert in his parachute when he could have had a day off for the Fourth of July was not in the original script: The desert setting that they were filming in was actually the salt flats near the Great Salt Lake, where it contained some decaying corpses of brine shrimp which, if the wind disturbs the sediments just right, can reveal an extremely bad odor, which he was not warned about.
Title Drop: "Today we celebrate our Independence Day!" And to make it more awesome? Bill Pullman ad-libbed that line.
The people that were waiting to the aliens in the rooftop of a building in Los Angeles. Including Tiffany who promised Jasmine she wouldn't.
Also those "scientists" that were diagnosing the alien without any security nearby despite the fact that they knew the alien wanted to kill them.
While he doesn't show much stupidity anywhere else, David Levinson asking Major Mitchell to fire a bullet at the alien spaceship definitely qualifies. Has the man never heard of gun safety? The bullet ricochets dangerously around the room containing what's left of the American administration and the only scientists on Earth with knowledge of the aliens' technology,
He's a scientist with either little or no knowledge of guns, he probably assumed that the bullet would just flatten against the shields instead of ricocheting.
Too Fast to Stop: The alien dogfighters, inexplicably, towards the end of the movie, even though they are stated to be extremely maneuverable.
Tropes Are Not Bad: There's a reason this movie spawned the "Big Willy Weekend" tradition.
Universal Driver's License: Hiller claims that he is one of the few fully aware of the alien fighter capabilities and that being a pilot he can figure out how it works. Parodied in that his first attempt in the cockpit ends with him going in reverse. Although admittedly the controls seem fairly intuitive, using dual joysticks. The movement directions being labled wrong by the scientists wasn't helpful.
Lampshaded immediately afterwards, when David asks him quietly if he really believes he can fly it.
We Come in Peace — Shoot to Kill: Completely averted. The aliens make no attempt to hide their intentions, likely because they see us as little more than pond scum.
What Could Have Been: The original ending involved Casse being disallowed to fly alongside the others, and so he straps an explosive to his biplane and performs the Heroic Sacrifice by flying it into the superlaser as per the ending that found its way into the film. It was determined to be a little bit too comical seeing a biplane match the speed of the fighter jets, and the reshot version allows us to see Russ make his decision as opposed to a suicide mission that just happened to be plot significant.
Homaged/Parodied in one of the later Metal Slug games as a cutscene once the Big Bad ship starts to fire its big beam. An antique plane flies into the beam and...
Wiper Start: A jet fighter version — as Vietnam War-era pilot (gone to seed) Russell Casse tries to ready his F/A-18, he almost fires a missile.
Russell Casse: [[Film/Airplane I picked a hell of a day to quit drinking.]]
Becomes a bit of a Funny Aneurysm when you realize that was probably the missile that failed to fire, meaning he had to die instead of just firing it and going home to his kids.