It is very common that your cat or kitten can get a small kitty cold from the stress of traveling especially the ones that have been on a airplane, so we recommend that you confine your cat to a small area for the first 72 hours like a bathroom or small bedroom, away from all other pets. They are scared and need time to adjust to there new surroundings. It is common to sprinkle a little Cat Lysine over there food to boost their immune system during this stressful time (I give this to all my cats all year round). Make sure they have access to at least two litter boxes per cat with the same litter we use, and fresh food and water. If you want to change their food and litter brand, then you should wait a couple weeks then mix it gradually so you don’t trigger upset stomach or runny stools or unwanted accidents. Have your cat introduced and checked out by your own vet within 72 hours of your kitty coming home.