IMHO it's being in the carrier, since they start complaining before they're even in the car. As a young college idiot I drove 3 days with a cat and a friend, and we didn't have a carrier. The cat found herself a "safe spot under a seat, and since it wasn't the driver's seat we let her stay there. She was quiet, seemed pretty calm, even slept. If I knew my cat would stay in a safe spot like that, and would get back in the carrier to go into the vet's office, I might let her out for the drive. But that's not gonna happen.

[–] MeatCat@dubvee.org 2 points 6 months ago

When I was in college I'd go visit my parents every other weekend or so. I always brought the cat so she wasn't alone in the apartment all weekend. She would just crawl up on the little shelf under the rear windshield and nap the whole way.