WMG / Cars

The Cars' bodies are made of Magitek Nanomachines.

• It's an Alternate Universe full of Magitek, and that + Nanomachines would explain a lot about the Cars' biology, faces, sentience, etc.

Mater is a closeted homosexual.

Jossed in the sequel. Why do people keep guessing this for at least one character in EVERY show?

• Because slash is fun. And it's obviously Sarge, which was practically confirmed by the subtext between himself and Fillmore.
• Maybe he is a closeted bisexual.

Satan made the cars

There, problem solved. You might be wondering why it was Satan and not God; it's because mankind supposedly was made in Yahweh's image so God cannot possibly be behind the creation of sapient, non-anthropomorphic cars.

The movie is a post-apocalyptic follow-up to Toy Story.

Why would a world be populated by vehicles with space for drivers? Because there was once someone to drive them. Everything humans made had the potential to become sapient, but only if humans (or other living things) imprinted personalities on them. This happens strongly enough with toys, by their nature, that they "wake up" almost immediately; with other things, this was not the case. Then the humans all died out, and over time, the cars slowly awakened with the degree of personalities they had received from the humans. (Americans love cars.)

• This could explain why older cars are recognizable makes and models while newer ones (from after the cars started "reproducing"), generally aren't. (They try to be, but they forget...) That would put the date of the apocalypse sometime in the early 1970s (1973-4 gas crisis?).
  • Sally is a 2002 Porsche 911 Carerra, Bob Cutlass is a 2004 Mustang, Mia and Tia are Mazda Miatas, the two lost minivans are a 2006 Saturn Relay and a 2000 Dodge Caravan, one of the Rice Burners is a Scion xB, etc. This isn't obvious because, as Marv said, all modern cars look like electric razors.
  • Sally, Mia, and Tia are exceptions. Bob Cutlass only has a Mustangish grille shape. The tuner's more like an xB than anything else, but it's a two-door, and xBs are all 4-doors. The vans are completely generic, no matter what Pixar says.
• Come to think of it, this also ties in with Dinoco existing in both worlds. (Wonder how much evidence there is for a unified Pixar universe?)
  • A lot. Pizza Planet vans are seen in numerous films and Bomb Voyage from The Incredibles appears in Ratatouille as a mime. Also, sentient toys could be malfunctioning robots which were invented by Syndrome in his world domination schemes, and Sentient animals and super-heroes could be a result of the radiation which eventually causes the world to close down in WALL•E, while the humans are away, Syndrome's robot cars form a new society, but are eventually destroyed and recycled by the WALL•E robots.
    • On that subject, did you notice the power line with the birds from the Pixar short "For the Birds" passing by in the film?
    • They went by too fast that we don't know if those were the same (organic) birds, or a Cars-verse automotive equivalent.
• Alternatively, the cars rose up and slaughtered their human masters.
  • I, for one, welcome our new automotive overlords.
  • Shades of Roger Zelazny's short story, "Devil Car," in which rogue cars "mono" their passengers (poison them with carbon monoxide) and run free. Something like this happened in the Cars universe. Now the cars act out a bizarre parody of human civilization...
• The cars could already be "awake". They hide it from humans, just as the toys do, and thus the toys never notice them moving on their own. (There were a few Audis that got careless in the '80s, and some Toyotas forgetting themselves more recently.)
• The Dinosaurs they were talking about in Cars 2 were the Humans, guess what's in their fossil fuels now.
• The revolution was started by Lotso. He does hate humans, especially after the Fate Worse than Death given to him. He's not mentioned because the cars didn't want him as their founder.
• Cars get rid of human confirmed by Jay Ward, the creative director of the Cars franchise

Alternatively, Cars takes place after Maximum Overdrive.

Sentient cars, machines with dangerous and even homicidal tendencies? This is what happened after the humans were forced into hiding!

• Supporting this theory is that at one point there's a recording of "The Star Spangled Banner" played by Jimi Hendrix, and the character listening to it even mentions Hendrix despite the fact that no humans are ever seen in the films.
• There's also the possibility that Hendrix was a car in the story's verse like the real-life humans who appear like Michael Schumacher or Queen Elizabeth II.

Actually, Cars is a post-apocalyptic distant-future follow-up to The Love Bug

Herbie was to the Vehicles what Caesar was to the Apes.

Cars and the Burnout games take place in the same universe

Both include a world fully designed to accommodate humans while distinctly lacking them, and feature self-piloting cars. Burnout would occur somewhere in the brutal past of Cars or in the bleak future, when society has dissolved and all the cars have turned feral, possibly due to The Virus.

The Cars world is not Earth, but a long-lost colony of Velocitron in the distant future of Transformers Cybertron.

The ancestors of the characters were Velocitronians who visited Earth, which is why their descendants have Earth car forms; they were cut off from other alternatives. Rather than return to Velocitron, they decided to forge a new world of roads to challenge their racing skills. To honor the humans' part in stopping the Unicron Singularity, they named one of the first major roads after an Earth locale, Route 66. Soon after, a remaining group of aggressive Decepticons attacked and hit the planet with a version of the transformation lock virus from Beast Wars. The Decepticons were defeated, but the Cars Worlders were trapped in vehicular form; even the data used in reproduction was corrupted. Eventually, the Cars Worlders descendants lost the capacity for transforming and evolved into the body styles of the film. The only remnant of the faded memories of Velocitron is a love for racing; those skilled at it are treated like we treat pro athletes.

• ...This makes sense, actually.

The Cars universe is our world after everything was automated, cars were intentionally given artificial personalities and put on a grid, and everyone died of something stupid (poison or radiation) that doesn't cause property damage.

The reason the cars have opaque windshields is because nobody ever drove once the cars were put on the computer-control grid. People could watch movies on the inside during long trips and give the outside more "personality". The cars are more squishy because they are made of super tear-resistant fabric over warping frames (unlikely, looking at Mater), or are Nerf cars, both of which are real concept designs (the former of which was available on the market a couple of years ago from BMW).

Something happened to humans at least 50 years ago that didn't wipe out electronics. The reason that cars correspond roughly to our current cars is that the classic-style cars were only made for collectors, and the more modern-looking cars were mass-produced. The cars can still fuel up and everything because the pumps are fully automated and/or they use some sort of hydrogen fuel cell that we have yet to invent, and the tractors were built as non-methane producing replacements for cows after artificial meat became popular.

• The cars could have been given the ability to converse because they had been linked to the passenger's perceptions, so they could talk to other drivers without getting out of the car.

The Cars are actually a race of car-shaped aliens.

First of all: cars don't have eyes. They speak English because they picked up our language and stuff from the Internet. Eventually, the aliens forgot they were not from Earth and actually believed they were real cars. Where are the humans? Read the above WMG.

The passengers are still in the cars.

They just never leave.

There are passengers, and they have the cars hooked up to their brains.

This is why the cars have personalities and voices and can move about freely (jumping included).

• This makes so much sense!

Lightning McQueen is Steve McQueen.

Continuing the WMG above, Lightning may be Steve McQueen with his brain hooked up to a car. "Lightning" is simply a nickname that he eventually gained after this happened.

• Jossed by the creators; McQueen is named after Pixar senior animator Glenn McQueen, who died in 2002.
• That may be true but that doesn't disprove the theory. And let's face it [Steve Mc Queen] 'is'The King of Cool

Lightning got shocked one too many times by Dr. Mater and lost large patches of his memory.

That's why he never remembers Mater's Tall tales even though he was there when they happened.

Lightning is a famous racer in a coma.

He was put that way by a terrible racing accident, and the whole movie is a giant dream sequence. When he first comes into this "dream world", it's more of a nightmare for him.

Sally knew that Doc was a racer.

During her time staying at Radiator Springs, Sally looked into Doc's garage and discovered his past. She was going to ask Doc about it, but she learned how much he doesn't want to talk about the life that nearly killed him. So she decided to keep it a secret from everyone, especially Doc.

This explains why she's upset at Doc for calling the news and the press to send McQueen away. When she said "Best for everyone, or best for you?", Doc realized that she knows.

The Cars universe diverges from the same Alternate Continuity as 9.

In 9, it is revealed that the Industrial Revolution never ended, and machines were given artificial intelligence. They turned against the humans and wiped them out.

The Cars universe is a more positive result of this. However, something happened that caused humans to disappear, leaving only the cars.

• Dolls build new machines, now with better personalities instead of just intelect like Fab Mac. Earth has slowly started to recover, with grass and otehr vegetables returning to world. No animal life tough. Yet. Dolls eventualy "died" and machines eventualy made themselves cars that were common in old world.

The Cars universe is set in the story of earth after a "Grey Goo" nanomachine disaster.

A grey goo disaster happens when nanomachines go out of control, copy themselves as they record everything, and reduce the surface of the earth to grey goo.

In the Cars universe, the goo eventually tries to recreate the world it remembers — but its memories are flawed. It remembers vehicles and roads the most, so it creates the world in that image - which explains why even the mountains look like cars.

Most of the above WMGs make no sense because Cars obviously takes place near the end of the 20th century/beginning of the 21st.

Seriously? Cars is from a post-apocalyptic wasteland? The passengers are using the cars like the chairs in WALL•E? This makes no sense. Look at the structures, the older cars like Doc Hudson and that really old granny car. There's no way those cars could have survived that far (at least a century) into the future for any of this to happen. The one with passengers in the cars makes a little sense, but remember that a lot of the cars in Radiator Springs remember a time before the interstate. That's in the 1930s, or too far back for your theories to be plausible.I know this isn't technically a WMG but it doesn't fit in any of the above because it applies to tons of them.

• There are machines that have lasted over a century; a case in point, the John Bull locomotive in the Smithsonian Institution was built in 1831, and on it's 150th "birthday", in 1981, the curator of the museum, at least the transportation part, fired up the engine and it worked.
• Or the factories/whatever makes new cars could be basing their designs on older models.

Cars is just Andy playing with Hot Wheels

The opening of Toy Story 3 suggests the idea that it's what toys truly experience during playtime. So a bunch of toy cars being played with would experience a whole different world. A toy car resembling Lightning McQueen even appears at Sunnyside.

• Made of Win.
• Totally plausible.
• Best. (and the most plausible) WMG. EVER.
  • Andy will become a writer when he grows up, and will be the most awesome writer EVER!
• I second this.
• This is further evidenced in the Toy Story Toon "Partysaurus Rex", where the toys truly experience the adventures Bonnie sets out for them during bathtime. This WMG just got even more canon merit!
• This is the most accurate and likely WMG that this Troper has ever read, and there is no way it isn't true.

HARV is a human being.

This movie takes place in an Alternate Universe

There are car versions of real people like Jay Leno and Arnold Schwarzenegger, there are real places and locations made to fit with it's automotive citizens, and the car versions of other Pixar movies imply that there are car versions of the Pixar crew working on animated car films. So that means that there must be a car version of everyone on Earth throughout history.

• So, there's a car version of Cars? Humans?
  • If it were true, there would be plenty of weird stuff on TV Tropes; some hilarious and/or awesome (Back to the Future? Speed Racer?) and some, mostly from darker fiction, horrifying (SCP Foundation? Homestuck, to some degree? Fallout? HP Lovecraft? Don't even get started on anything above 18+.)... And what about some of the terrible Real Life historical or present-day events? It's probably for the better to assume that the Cars universe is different enough that anything which doesn't fit the theme never happened. The sequel might change the tone a bit edgier from the original, judging by the trailer, though.
  • Maybe "Humans" in the Cars-verse is their equivalent of "Furries"...
  • So what would the Cars-verse version of those dragon/car tailpipe pics be, UFOs and train tracks? And what about those airplane-girls?
• Garagestuck: Jeep Edsel, Dodge Studebaker, Royce Lasalle, Jordan Harley and their weird alien counterparts Carcat Vantage, Vespa Circuit, Nissan Lion-Peugeot, Gumpert McLaren, Elva Aston, and Ferrari "Portia" (to name a few) and mysterious exiles like Wandering Volvo and Piston Merchant play a game authored by the brilliant and eccentric Austin Heeley.
  • Roadless: On a planet where trains are the dominant life form and roads without rails don't exist, some young locomotives slated to be assigned jobs according to an oppressive caste system are instead drawn into the same game played in Garagestuck. A series of magnetic railguns mounted on train cars protects their planet from meteors until an evil flying space train comes to tow their moon into their planet, prompting them to flee using the game.
• Backfire to the Future: Doc, a Delorean, falls for a train from the old west. Marty is (inexplicably) the hoverbike from Star Trek (2009).
  • Biff starts as a sports car but, after being humiliated by George, becomes a tow truck.
  • George is a lemon who used to be bullied by practically everyone until "Carvin Klein" encourages him to stand up to Biff. His novels enable him to afford Biff's services on a regular basis.
  • For being a Delorean, Doc is considered worse than a lemon.
• HP Driveshaft's In The Underground Parking Lots Of Lunacy: It'd be like Top Gear's Arctic road trip minus the sled and plus nightmares. The cosmic horrors would be those massive mining machines that look like giant buzz saws.
• History: President Lincoln Convertible has been shot by John Wilkes Tollbooth!
• Mechanic Who: A time traveling alien time machine called The Mechanic travels through time with his car-panions.
  • Doc Hudson is a Time Lord who regenerated into McMissile! The Daleks are the Anthropomorphic Personification of everything that can ruin a car from rust to giant boulders combined with a hatred of anything more mobile than they.
• Transformers is Beast Wars in reverse with strange fleshy creatures disguising themselves as vehicles.
• Car Wars: The plucky Dodge Skyliner vs. the corrupted Darth Vespa (could also work for Spaceballbearings - Barf is the Winnebago!).
• The Trailer-hitch-hiker's Guide To The Galaxy: A Ford goes on an amazing adventure with a Dented pal.
• The Matrix: The title character is trying to protect a Scion.
• Repo!: The Saw of the Cars-verse.
• Tunnel: A mute Chevelle battles BluCaDOS (Blueprint Carform and Disk-brake Operating System) with the Aperture Science Chassis-Mounted Tunnel Device.
• Super Cario Brothers: Featuring Alfaromeo and his brother Lamborghini.
• Motor Man: Dr. Lexus's Motor Man faces off against Dr. Wildfire's robotic creations.
• ''
• Inspector Gadgetmobile
• The Nucleons: Atomic-powered flying cars in a retro-futuristic animated sitcom world! And speaking of which...
• Peelout: Atomic-powered cars live a bleak existence in the radioactive ruins of a retro-futuristic world.
• The Cars: The only driving/racing simulation game in the entire Cars AU.
• Homecar Driver: Mainly known for the cmail animations.
• My Little Tractor: Friendship is Magic brought about the "trucktor" subculture.
• The DMV Foundation: Mysterious Paranoiamobiles unwittingly make eldrich abominations and general creepiness stronger as they try to stop it while accidentally leaking all their documents to a creepypasta wiki.
• Diesel: The main video game digital distribution platform.
• Pacific Rims: In an attempt to defeat alien submersible megatanks rising out of the Pacific Ocean, the nations of the pacific rim build giant 4-wheeled robotic rovers armed with weapons. Due to the extreme mental load, each car can only control one tire at a time, leading to four cars that are drift-racing-compatible piloting the massive meta-vehicles.
• Driving Under the Influence: DUI 1 and two had you crashing into other cars for points. DUI 3 onward starred criminally bad drivers carving paths of destruction across fictional cities in full glorious 3D. DUI V had three protagonists: Franklin Lincoln, Michael Towncar/De Lorean and Tractor Phillips.
• Minecart: A highly addictive game where you are a minecart who must craft rails for you to travel on and then lay them through a voxel sandbox world to get more resources for better rails, etc.
• Jurassic Parking: A wealthy car tries to revive the same-as-real-life extinct dinosaurs mentioned in Cars 2, to create a zoo. They get loose on the island the zoo is on thanks to the treachery of the computer programmer who sold out to a rival genetics company, and a lawyer car and one of the tour guide cars get torn to shreds by a T-Rex.
• Parkémon: A popular RPG series created in 1996 by Nintendrove. Players drive across the land, searching far and wide for Parked Monsters (Parkémon) in an attempt to defeat the Elite Four Cylinders. Also accompanied by an anime that follows the adventures and misadventures of Ash Clutchem and his trusty partner, Pikavroom. Already up to its seventh generation, which added new favorites such as Charjabus, Roll-it, Toucamber, Gumtires, and Type: Neutral, but Engine-Wunners continue to clutch to their Carizard, Wheelasaur, and Draftoise plushies. The prior generation introduced a “Mega Evoboostion” that allowed for those three, as well as other popular but unviable species such as Gardemotor (please don’t look up that one without safe search).
  • Hey, Pixar? Will you please find a way to include some of these parodies in ''Cars 3''?

The cars are able to move because they are Merchandise-Driven.

Rule of Symbolism.

Mater's Tall Tales are all true

Except for the bits at the end where he says Lightning was a part of them. Mater just says that to mess with him.

The Cars world co-exists with the Thomas & Friends world and vice versa.

Think about it. Both universes have Animate Inanimate Vehicles have little to no explanation how they came about, and both have very very little humans present (and in Thomas's case they're rarely shown).

• But there are humans in Thomas's world, even if there's only a few of them, which makes that world a bit less frigidly horrific. As far as I know there aren't any humans (at least in Cars 1) and the only "living" creatures were dinosaurs and they died millions of years ago.

Cars, like monsters, can slip into a parallel universe.

Maybe when they go in a garage, they can drive out through the back wall into their world? It certainly makes car wrecks in our world much more horrifying, though.

Cars takes place in the normal Pixar universe, but it goes like this...

At some point during the Pixar universe timeline, sentient cars built by the humans rose up and took over. The humans who weren't killed went into hiding in the places that the cars couldn't get to. At some point, though, the Cars universe falls apart. Why? Lack of fuel. They need it to run. They haven't developed many alternative energy sources. Only the richest cars of all could afford to be converted to solar power. Lightning McQueen couldn't, because after his racing career died (when the fuel was running out, racing was one of the first things to go) he spent all his money on car hookers, and car drugs like car-caine. He dies of an overdose, and the rest of the cast who haven't died are forced to live in this apoc-car-lyptic world. Eventually, nearly every car dies off. The few that are left get destroyed by the uprising humans, who saw the rapidly falling car population as their chance to take back over. They do so and rebuild the world, eventually into the futuristic one we see in WALL•E...

• I kinda thought that it may be backwards: after the end of WALL•E, the humans slowly evolve into cars, who went through the same stages and time periods and styles like we did, which is why there are so many parallels to our world and the Cars world.
• But what about Cars 3?

Acer's Start of Darkness came after a horrific injury.

...when Alice's dad tried to park his Skylark in Acer's trunk...

McMissile is...

...actually Doc Hudson, but altered for his role as a spy car!

• BEST. WMG. EVER.

...actually Michael Caine as a spy car.

Lightning McQueen and Sally are like parental figures to Mater.

• Their conversation at the beginning of Cars 2 sounds like a mom and a dad talking about the dad taking the child on a business trip.

Our own world is the Cars world after a Zombie Apocalypse.

• We are The Virus that spread to infect innocent cars all over the Earth, robbing them of life and sentience and rendering each hapless victim into a shambling, will-bereft chassis that moves only at the behest of the contagion. Having reduced all mechanical life to inert automatons, the organic infection then took on forms suited to control their lifeless carcasses, and assimilated their individual histories and personalities into ourselves, until we came to believe we were the planet's rightful inhabitants, and always had been.

Zundapp is an ex-Nazi.

• Uh, he's a late '50s model and WW2 ended in 1945.
  • There appears to be some discrepancy between some characters' ages and their model, so it's not impossible. Well, either that or he's a Neo-Nazi.
    • This troper agrees as Sally is a 2001 Porsche. If model is in relation to age then that would mean Sally is FIVE YEARS OLD by the first film. Making her and Lightning's relationship VERY creep.

Francesco is Agent Simmons.

• After Agent Simmons' dies, Primus decides that for capturing and torturing Bumblebee in the first movie and being a general jerk in the series, as punishment, he will be reincarnated as a vehicle in an alternate universe as penance. This is his Purgatory.

Cars in this world can adapt, same way as humans in our world can.

It would help explain some things, like how they are still around after all these years.

New cars come from...

• A male and a female car who want to have a kid go to some sort of "factory" and help "design" a baby car, which is built to specifications and based heavily on the parent car types. "Defects" are when the system malfunctions, Lemons propigate because they get together and make more of themselves.
• Cars are techno-organic constructs, and thus can have babies like humans can.
  • Or they lay car "eggs".
• The Allspark.
• Wherever Rodney Copperbottom came from.

Cars and other vehicles "evolve", at a much faster rate than organic life does.

Or scientists and engineers figure out ways to improve the species, and then incorporate these designs into the next generation. This is why older cars are different models than younger ones.

• "Fashion" could also play into this, as new cars are created with popular features of the time, or they could modify themselves.

The Cars universe is actually a level of "car heaven".

Cars from our world that were well-loved by their owners are reborn into this world when they "die".

• Jossed: Several characters such as Lizzie's husband and later Doc are established to have passed away.
  • Not necessarily; maybe they’re Deader than Dead?

Rust is a disease

It seems like in the two movies, rust can act like leprosy or be an indicator of one's rapid aging. Maybe for Mater's case it relates to the former, his mind can't catch up with the aging and reverts him to a child like demeanor.

The mixed critical reception of Cars 2 was mostly because Bruce Campbell's character got killed

Come on, nobody wants to see the Man with the Chin dying.

Red is part animal.

He never actually speaks, just occasionally vocalizes and sounds his siren. Since he's a firetruck (and I always imagined elephants would be depicted as firetrucks in the Cars universe), we can maybe assume he's part elephant... After all the tractors are cows and Frank the Bulldozer is a bull, etc.

Furthermore Tony Trihull, the lemons' combat ship, is said to be part shark, despite having human dialogue.

Cars is a distant sequel to Stephen King's Trucks

In Trucks some unknown force causes vehicles to become sentinent and rebel against their human masters. Over time, that same mysterious force caused the cars to keep evolving into the living, talking cars from the movie, while Humans eventually became extinct because the smarter cars didn't need them anymore and exterminated them.

The Pizza Planet truck is behind the car versions of the other Pixar movies seen in the end credits.

In this universe, as we see, it's alive. It makes movies based on the weird things it sees in its travels. Also, the movies aren't completely the same as ours since it's going off very little information, just a few scenes happen to match up. Notice how there's no car version of The Incredibles or Finding Nemo, since it doesn't appear in the former and is in a hypothetical situation in the latter.

Cars takes place in a world after humans, but not through any violent car uprising.

At some point, humans started making vehicles and machines with artificial intelligence. After the humans died off, perhaps in biological warfare or a nuclear war, the cars still remained. They all had some degree of self-preservation instinct programmed in, so they would get gas and repairs, and try to continue life as normal by doing things they were already programmed to do, like build more machines. At some point, a glitch in programming caused some machines gain more sentience and intelligence than the previous machines. They developed stronger self-preservation instincts, along with traits like curiosity and creativity. These cars lasted longer and replicated their programming for new machines, in a process something like a car evolution. Less intelligent machines continued to be built for work purposes, giving them an equivalent to animals.

• Well, Word of God now actually confirmed the car uprising, so...

Francesco Bernoulli is bisexual.

I mean come on look at how he's paying so much attention to Lightning.

The passengers are the cars' emotions.

• I love how we are connecting newer canon to older canon. Tau Ceti - 10.4

Chick and Ripslinger will meet in one story.

It'll be a "Strangers on a Train"-Plot Murder story where Chick and Ripslinger want Lightning McQueen and Dusty Crophopper so Chick will try to kill Dusty for Ripslinger and Ripslinger will try to kill Lightning for Chick.

• It's unlikely that Chick would go that far, as he was never shown trying to kill anyone (although he is perfectly fine with crippling), while Ripslinger was. They'll probably team up for a revenge scheme, but when Chick learns that Ripslinger plans to kill the heroes, he will object or at least be horrified.

Cars are originally Human

Jalopnik describes a plausible theory about why there are only cars in the Car-verse.

Tiger Woods is a VW Golf

The Pun's too obvious not to Passat Up!

If Cars 2 is (somehow) in the timeline, Cars 3 is a midquel.

That would explain why nothing in Cars 2 shows up in Cars 3.

The entire Cars universe operates on Blue and Orange Morality

It's practically confirmed that Vehicles are built to fulfill a designated purpose/s, which they seem oddly happy to do their purposes (I'm guessing cars such as Camrys and Honda Civics are built to be the civilians of the Cars world), that aside, Cars likely operates on voluntary mechanical evolution, which we can see in Cars 3, in which the main antagonist is a next generation of race car, we can also see this with Lizzie, who is a Ford Model T, it's likely before the Cars came into existence, their was a similar situation with Horse Drawn Carriages, which probably weren't actually horse drawn, before Nicolacariage-Joseph Cognot created the Fardier a Vapuer, and Karriage Benz built the Benz Patentmotorwagen, which brings up an important question: who built the Carriages?

Lightning has many relatives he doesn't know about

And most,if not all,of his appearances in Mater's Tall Tales are actually them. That's why Lightning doesn't remember anything despite supposedly being there with Mater,and after the times it really was him,he got his memory erased in one way or another (electrocuted by Dr. Mater,brainwashed by Mrs. UFO,lost memory due to time travel paradoxes). Mia and Tia appearing in "Private Eye Mater" are also not the ones we see later.

The Cars are the Toys of a child in Toy Story

Cars was a Toy Line similar to Hot wheels, and one kid loved Cars so much that he had every one, and created elaborate personalities and lore for the world, hence why there's so many unfortunate implications about the Cars universe, and the Cars believed themselves to be the only beings in the universe, before Cars 2, the kid became obsessed with James Bond, hence the sudden Spy Plot, while Cars 3's return to racing is because of the Kid rediscovering his love of Racing.

The movies take place in a distant, transhumanist future

Humans created the technology to be anything they wanted and thought old-fashioned cars and planes, etc. were cool. They're still born as humans and maybe some fringe communities still live in human bodies, but most people can afford to become whatever they choose. They still have human features like tongues to soften the neural impact, but they're mostly able to upgrade at will.

The entire series is just Claire "Lightning" Farron From Final Fantasy XIII having an insane fever dream during her time as a Cie'th

While invading Eden with the rest of the party near the end of the game, the party encounters a futuristic car race "Grand Prix" on their way to face Barthandelus. This event sticks in Lightning's mind and when she briefly transforms into a Cie'th she has a dream about being a sentient car in another universe.

Someone orchestrated a cover up of the human race.

In this theory at some point humans did make the cars as evidenced by their windows. Then humanity was wiped out either due to an apocalypse or an uprising leaving behind sentient machines. In the wake of humanity's demise someone decided to cover up the existence of humanity possibly to cover up a Genocide. To this end THEY wiped the slate clean and created a new world populated by the first cars. THEY used human history as a blueprint for their new world. This the existence of such oddities as Jay Limo. Any "history" for the world before cars were invented was probably heavily compressed because THEY didn't want draw attention to it. So there were stories of a car Jesus but not car crusades. Cars like Stanley the founder of Radiator Springs were the first real generation of cars. And then the history of the world was recreated up until the time of Cars 1. Presumably this will continue up until the time humans were wiped out. What happens after that point is a mystery. At the time of the cars of the world are kept to their assigned functions as a way of keeping them from questioning the relatively flimsy set up for their world. When Dusty the plane switched his career to racing that could be the first crack in this class system. Maybe he was then sabatoged in an effort to get him to return to crop dusting (and firefighting is still closer to crop dusting than racing). Along with the conspiracy of lemons (as seen in Cars 2) Dusty could be the first unplanned variable in their plans or he could just be another distraction. In any case there is much more than meets the eye when it comes to the world of Cars.

Biological animals exist in Cars world, and are treated by vehicles as cryptids and/or mythical creatures.

In first film, we can spot California flag that looks similar to the real life flag of the state due to having a normal grizzly bear. Yeah, you heard that right. Not some Fantastic Fauna Counterpart of bears that this world has, but a normal, biological bear. This could mean that vehicles see biological animals like bears as mystical creatures in similar way as to how we humans perceive unicorns, pegasi, dragons, griffins and phoenixes. Why? In real life, many countries and other administrative divisions have mythical creatures on their flags, meaning that in Cars world, biological animals that are normal for us humans are seen by vehicles as fantastic beasts or cryptids, that may or not be real, similar to Bigfoot, Loch Ness Monster or Thunderbird. This could also mean that some aspects of vehicles culture look different than in real life - for example, in The Lost World (1912) Living Dinosaurs are replaced with modern day Amazonian fauna, with theropods role being taken down by jaguars.