Like mentioned for Nash Bridges, most production companies have multiple copies of a car.
Dukes of Hazzard had two Chargers for show and close-up work. These were rarely driven, and kept in top-notch shape. Then they had a fleet of others, a half dozen at times, that were the “drivers”. Meaning these were the ones blowing down dirt roads or doing the bootleggers’ turn, or driving through town, etc.
These were Chargers of various years mildly modified to all look like the '68 or '69 they used, often with different engines (six bangers, 318s, some 440s for certain stunts) and some were automatic while others were manual. Some had interiors, most didn’t, most had functional doors, some didn’t. It all depended.
Then they had a couple of “jump” cars, with modified suspension, reinforced frames (or bodies anyway, the Chargers were largely unibody cars) and eight-point roll cages. Most of these also had modified 340s and 440s for the power needed for the jumps. Most jumpers were essentially ruined in one or two stunts, at which point usable parts were removed for use on the other cars.
In Miami Vice, the original Ferarri Daytona Spyder was a Corvette-based kit car. From what I understand, they never had an actual Daytona for any filming. I’ll assume they had more than one kit car, but I haven’t read that for sure.
Anyway, at the time, Ferarri was embroiled in lawsuits with kit builders, and having such a kit on a popular TV show wasn’t helping. Ferarri negiotiated with the producers to “lose” the fake (they blew it up with a rocket launcher- I don’t know what happened to the actual car) and they switched to an actual Testarossa for the rest of the series.
Here, again, they had one real Testarossa for interior and close-up shots, and two kit cars (actually special-built tube-framed stunt cars with fiberglass TR bodies) for the high-speed stunt work or anything that might cause damage.
In Con Air, I’ll assume they had multiple Corvettes- at least one for close ups, and at least one more for driving and stunts. However, I do know that, when Colm sees the car after it’s flown through the tower and crashes upside down, that IS midyear 'Vette suspension clearly seen. Whether they destroyed an actual Corvette or had a junker for the upside-down scene is unknown.
In XXX, actually they had three GTOs, all actual '67 GTOs and not LeMans’s or Tempests. A fourth was built as a promotional/show car.
Some movies used one-off show cars, or manufacturer’s exhibition cars. Demolition Man, for example, used a GM concept car (several actual ones plus some mockups for stunts) as the police cars, and a bunch of lesser-known concepts for background and “traffic” scenes.
They, of course, also used up three Olds Cutlass 442s- one a closeup/interior car, and two drivable junkers for the chase and damage scenes.
The movie Wraith used a Dodge concept car that was also used as a land-speed test racer. Again, they had the one original as the closeup car, one drivable mockup for race scenes, and one undrivable dummy for crash scenes.