Wow I think I would go crazy too with the screaming. I wonder half of the time what they are thinking in their little head that made them act the way they do and that is what makes them funny sometimes
My yorkie boy doesn't scream in the car but pukes nearly each time he travels in the car.It is gross when you are unprepared for it.The thing is, I don't think he'd puke if he would stay still in the car.From the minute he gets in to the car, he'd move and move and doesn't stop moving and then he pukes.