Preparing To Travel With My Cat

I am going on a 4 hour flight with my cat. Should I not feed him anything, nor let him drink, an hour before hand? Should I feed him while I'm at the airport, on the airplane, etc.? I don't want him to have to go to the bathroom until we arrive at our destination.
BTW, when he doesn't have food in front of him for some time, then starts eating again, he usually throws it up, so I'd like to prevent that...

If depends on how you normally feed him. If it's free feeding, I would take the food away an hour or so before you head to the airport. If you feed him at specific times of the day, either skip the last meal before the flight or give him just a small portion. I wouldn't worry about taking water away. You can put a puppy pad in the carrier in case of accidents.

I don't normally feed my cats at the airport unless I have a really long layover between flights. I will provide water if it's a hot day.

When you get to your destination just give him a little food, may 1/4 what he normally eats. When that has time to settle, give him a little more. That may help prevent the throwing up.

Does he usually pees/poops in the carrier when you take him in the car? If not, he'll most likely won't do it in the plane. Personally I was feeding my cats during the flight because well, I didn't want them to get hungry, but 4h seems short enough not to. I wouldn't however take the water away - you might have noticed it yourself that air in the plane is very dehydrating. I was actually even giving my cats water through syringe. Their proper hydration was more important to me than the mess they could potentially create, although to be fair, I knew it was unlikely they would pee in the carrier.
Good luck and have a safe flight!