also see Cat Travel
When I drive to visit my in laws for the holidays, I always bring by Maine Coon cat. In order to keep her calm during the trip, we put her in a carrier, and put in a few toys with cat nip. She will zone out pretty quickly after that.
When traveling with my cat we like to bring along his favorite chew toy and a portable litter box. It works great.
My male cat strangely enough likes to ride in the car. He doesn't even need a carrier, but I still use one for safety reasons. I just put him in the backseat and I give him a few of his favorite toys. The best thing to make a cat comfortable is to put their favorite toys and blankets in there so it feels like home.
If you are going to travel with your cat, bring a crate with a comfortable blanket so the cat doesn't get stressed out wondering where you are going. Bring water, food, and treats so it doesn't starve. You could even bring some of the cat's toys so it can feel at home and be entertained during the trip. Any medications your cat is on should be taken on the trip as well.
also see Choosing Between Cat Travel Carriers for Maximum Safety
also see The Top 4 Cat Questions Answered
also see Finding Pet Friendly Hotels
also see Choosing Between Cats and Dogs for Pets
also see Bloodwork in Cats
also see Feline Blood and Lymph Conditions and disorders