Keep any stress to a minimum by leaving a small tray of food in the cage. This will help a distressed cat relax and take his mind off the journey. If at all possible, slot a small amount of bedding into the carrier to help the cat settle down. Distracting the cat's attention from the impact of the journey should curb any problems you may experience transporting the cat.
Similarly, add a couple of cat toys and cat accessories to the carrier if you are embarking on a relatively long journey. The cat will need some mental stimulation to compensate for the lack of space.
Be gentle when carrying the cat carrier - avoid holding the carrier at an angle where the cat might feel uncomfortable. If you're loading a cat carrier into a car, place it in a secure position where the carrier cannot slide or flip should you be traveling up or downhill towards your destination.
Finally, never try and place two cats in one cage, even if they usually tend to be mutual towards each other's company. In such confined space, cat scratching may become a problem, and you don't want to run the risk of cats fighting should a journey last for any length of time. Its also unfair on both cats to keep them in such a restricted place.
Persian Kittens and Exotics ...
Kittylicious on Cat Carriers
If your cat is not keen on entering your new carrier don't try and force the issue. The cat may just need a little time to become accustomed to the idea spending some time in the carrier. Cats are independent creatures by nature, and will not take kindly to being shepherded into the carrier. The cat may lash out and scratch if it is hesitant to enter the cage, which in extreme cases could lead to diseases such as cat scratch fever.
Try and buy a spacious cat carrier where your cat has at least a little room for maneuver. Traveling in a carrier can be an extremely stressful time for some cats, so make sure the cat cage does not seem too claustrophobic.