I have driven chickens pretty long distances to chicken shows.
I usually just use cardboard boxes.
Be sure to not overcrowd and to put plenty of air holes (especially near the top) so they don't overheat.
It helps if you can set the container on a level spot in the car, not slanted. If it's slanted, the chickens may choose the high end & then slip around lots.
Also, I would STRONGLY not recommend a perch. They would probably not be able to hang on well during stops and turns, and would end up falling, potentially twisting their legs, banging against the perch, etc.
Special tip: To give the chickens better traction so they're more comfortable & less alarmed by turns and stops, put a piece of old carpet on the floor underneath their shavings (This is especially important if you do use a plastic crate). It should be big enough to cover the whole floor if possible, so it doesn't slide around too much. Carpet is better than a blanket or towel, because it will retain its flat shape and not slide around much or curl up.
