If you plan to travel with your pet, start out with small trips first before going on long trips. Be sure to pack a pet's own food and water to avoid upsets on trip. Some animal's stomachs will become upset on food or water that it is not familiar with. Pets should be confined in carriers while traveling. Your pet will be unable to leap from open doors or interfere with driving.
Dog harnesses are available that hook to car seats.
Sedatives from your veterinarian can be given to jittery pets for unavoidable traveling. Otherwise if your pet doesn't like traveling it's better to leave him with a sitter. Be sure to have identification on your pet while traveling. Be sure to include area code with telephone number. Two collars are good in case one falls off.