If your pet is not used to being in a car, take a few “fun” short rides
before your trip, gradually increasing the length of time spent in the car.
For longer trips your cat will probably be safer and more comfortable
in a carrier.

• Pets should NEVER be allowed to put their heads outside the window
  when riding in a car. Dirt particles can cause injury or infections and cold
  air taken into the lungs can lead to illness.
• Plan ‘snacks’, exercise and rest stops about every two hours if you’re
  taking a long drive. Bring a water bowl and adequate water for the day.
• Give the main meal at the end of the day. Dry food is more convenient but
  if your pet needs canned food, dispose of any unused portions if they
  cannot be refrigerated.
• Do not leave your cat in a parked car for a prolonged period of time.
  If you must leave your pet in a parked car, lock all doors and open
  windows enough to provide good ventilation, without allowing
  your pet enough room to jump out or get its head caught.
• Remember, on hot days, the temperature in a parked car can rise to
  dangerous levels in just minutes and your pet could die of heat stroke.