The telltale signs are everywhere. The cat has been sleeping on the car again, and the hood and windshield are covered with paw prints. Cats don't view property the way humans do. In their eyes, anything that's unoccupied is available to use as a place for a quick bath and a nap. While you may never get the cat to respect your ownership of the vehicle, there are ways to keep the cat from jumping on the car.
How to Stop a Cat From Jumping on Your Car
Use an electronic device that emits a high-pitched noise or a burst of water when the cat comes close. Most pet supply stores sell electronic cat deterrents.
If your car is under cover, put a motion-detected animal control device such as a ScatMat on the hood or roof. The tingling sensation when your cat lands on the device will discourage jumping up on the car for a nap.
Put a vinyl mat designed to go under a rolling desk chair on the car, bumpy side up. The tiny spikes on the mat will be painful, but not harmful, when the cat lands on them, and he will quickly learn to stay off the car. Although the mats are thick and rigid, it's possible to cut them so one mat would give you a piece for the hood of the car and another for the roof. Office supply stores sell them.
Use X-Mats on the hood and roof of the car. These plastic mats are designed to deter pets. The raised bumps are uncomfortable underfoot when the cat lands on them. Most pet supply stores sell X-Mats.
Invest in a car cover. While it won't deter the cat, it will protect your car from paw prints and scratches.
If you can, give the cat something else to nap on. A stack of wood crates or cardboard boxes about the same height as the roof of the car could provide a happy alternative for the cat. Put them as close to the car as possible, and sprinkle some catnip on the top carton to entice the cat.