Our cats travelled from France via Hong Kong to Auckland.
The plastic boxes they were in are great and roomy - the cat has to be able to stand up and their ears not touch the top of the box.
They have food and water on loading and water is topped up. They also travelled with some biscuits which they had at some point on the journey - I can't remember now, probably on landing in NZ. In HK they remained sealed in their box, but between flights their boxes did at least go to an air conditioned specialised unit - or so we were told
They had old towels/clothes in the crates with them, for comfort and for soaking up anything I guess!
Our cats range from between 5 and 17 years old and they all coped fine and have settled into NZ life with no problems