feliway is a cat pheremone, it is not, strictly speaking, a sedative, but it does have a calming effect on cats. Smidgen, when brought from Cheshire to Kent had it sprayed in his box and he let out maybe three squeaks in the entire trip. On the way to the vet the other day, without benefit of feliway, he squeaked all the way there and back. It is also useful if you are introducing a new cat to your present brood, or if taking a cat to unfamiliar surroundings. You can either get spray (useful to topical applications) and a plug-in version which works like plug in air fresheners, but is to soothe the feline population. Does not smell unless the house is kept really enclosed, but it works miracles.
Oh and the cage sounds just great. Rememer to check it is fastened well, some have four fastenings, not just the ones at the top.