Summarize this article:

A common worry when moving a cat is that the cat will need to eat, drink, or do its business. In general, when your cat goes into the carrier, it will go into hiding and resting mode, and won't want to do these things, anyway. To make the cat more comfortable, however, don't feed them anything, so they'll be able to ride without having to go to the bathroom. Some people suggest withholding food from the cat for 8 hours, if your cat gets car-sick regularly. If you're going on a longer trip, though, it's likely the cat won't eat during that time, so it's better to feed the cat normally leading up to the drive. If your trip will last less than one day, you don't need to worry about food, water, or bathroom breaks for the cat, and until your cat has a special medical concern it's much better to just leave your cat in the carrier while you're traveling, until you arrive at your destination. After eight hours or so, your cat will need a break and need to be let out for a trip to the litter box and some water. If you're going on a multi-day drive, you can let the cat out of the carrier in the evenings at the hotel, or wherever you're staying. There, you can provide food and water, though cats will commonly only be interested in drinking a bit and using the litter box. Never, under any circumstances, leave a cat in the car. Cars can overheat extremely quickly, making them death traps for your pet. Leave the litter box easily accessible until the very last minute, when you're ready to put the cat into the carrier, then clean up the litter box and make it the last thing you bring, or discard. If you have an appropriately sized litter box, most cats won't try to use it to do their business. It's not recommended that you try to use a big carrier and put litter inside. Once you've got the cat inside the carrier, put the carrier in the car, or whatever you're moving with, and leave the cat alone as much as possible. It's common to keep the carrier covered with a light blanket, as long as there is enough air circulation. Making the space dark can help to calm the cat down and encourage them to sleep. Don't stick your fingers through the cage, or move the carrier around, or attempt to let the cat out of the carrier. Just leave the cat alone to calm down. Try to keep the radio off, or very low, and keep your voices as low as possible during the trip. Loud sounds can be quite agitating for your cat, so Try to keep things no louder than the gentle hum of the air conditioner.
Don't feed the cat before putting them in the carrier. Keep each day of a drive to eight hours or less. Give the cat the chance to use the litter box before leaving. Put the cat in the carrier and don't take the cat out once you've arrived. Keep the car cool and quiet.