Cats are not good companions in travelling. You can put dog in back seat and he is happy. But cats may dig their claws into your neck.
Here is list of must have travel accessories that you should take with you when cat is your companion:
1 - Clean health report of your pet
2- Identification if it runs away
3 - First Aid kit
4- Small Litter Box
5- Water
6- Food
7- Cat Carrier