A complete search of the internet has found these results:
in the car is the most popular phrase on the web.
"in the car" refers to something that is inside of a vehicle. "on the car" refers to something that is physically sitting on top of the car or something having to do with the car (such as a license or tickets).
12,000,388 results on the web
I saw you plan that in the car.
Oh--I left my juice box in the car, Mom.
We're in the car, babe. Let me know if you need to find the car and I will honkl.
I left my bag in the car. Could you please get it for me?
I was attacked by bees in the car. It was terrifying.
Come on, Jenny, get in the car, please.
Just like we planned in the car on the way here.
Once you get in the car, there are various ways of making the car go where you want.
I want to go play my Nintendo Switch in the car. Could you unlock it please?
There are no books in the car.
You ate his yogurt in the car.
Get in the car before I bite your head off.
There was that episode in the car you mentioned earlier.
We were in the car when the police officer pulled us over for speeding.
307,297 results on the web
There doesn't seem to be any license plate on the car.
Are there any police sirens on the car behind us?
Where is your drink cup? Did you leave it on the roof of the car?
I believe that there are spare parts still sitting on the car.
A traincar is often referred to as a "car." You can put many things on the car of a train.
On this car, you will find dining service and some vending machines for your convenience.
Is their still snow on the car or did you scrape it off?
There is too much rain on the car windshield for me to see outside.
On the car or off the car, it's still dirt!