As you know, we recently moved from Vancouver to Toronto which is about 4300 km. Our cats came with us on that move. Before I start, there is one thing I hate and that was when people would ask me what we were doing with our cats when we moved. We are bringing them. It never even crossed our mind to leave our pets behind, they are apart of our family and they are completely capable of coming with us.
That being said, I was very anxious about bringing them along especially because Gizmo is a very anxious cat himself. I read horror stories online (of course) and also just plain felt bad. We were moving over a period of 2 long days which is not great for the cats.
When travelling with cats and well, animals in general. You have to figure out what you want to transport them in. Are you going to bring them into the cabin or put them underneath? My suggestion is that if you can, bring them in the cabin with you. Make sure you check your airline restrictions on the carriers as well.
We did our research and it is not recommended to sedate your pets when going on an airplane in case of complications, but a Vet will guide you to go into any pet store and get this liquid that is supposed to calm them down. We tested it 2 days before to make sure there would be no allergy. We did use this the day of and I think it worked on Kitty but Gizmo was way too anxious to even care about any medication telling him to calm down lol.
Try to get them to drink some water and eat a little before and if they do, make sure they go to the bathroom. If they are too nervous to eat, drink or go to the washroom, don't worry. My cats hardly ate or drank anything. Don't worry about them going in their kennel. Animals usually don't soil their beds unless they are still young and don't have much control.
Warning: The airport makes you take your cat out of its carrier and carry it through security while your kennel goes through the machine. Wear long sleeves and maybe bring a harness and leash just in case. We didn't have one because I wasn't prepared for this. Gizmo also scratched my arm up good.
Put one or two toys in their carrier so they have something they know. My cats didn't notice them but it doesn't hurt.
When you reach your destination, your cats will probably be so giddy to get out of the carrier you will realize they are fine. The most exciting part for my cats was when their cat post came. It was something they recognized and it had their scent all over it. They immediately jumped on it so try to bring something that is theirs from home. It will make the transition easier.
In the end, everything worked out and it really wasn't that big of a deal. They lived!