I can pretty much guarantee you that you will need a health cettificate and rabies vaccine at least. I have flown many times back and forth from Tx to Alaska with our cats and each time the airline has required both, coming and going. The health certificate has to be no more than 30 days old and you need proof of the rabies vaccine date as well. Have a nice trip :)
http://www.cdfa.ca.gov/ahfss/Animal_Health/FAQS.html#Pets
The above site says there is not much restriction by the state but that the airline might require a health certicate, so definitely begin with the airline. The only thing it does not address specifically is when the animal is coming from another country. It mentions that a cat from a "rabies quarantine area" must have a rabies shot, but doesn't say whether a rabies quarantine area is one with a recent rabies outbreak, or just the entire British Isles for example, where they have such tight rabies controls.
I have travelled to and from California from Oregon with cats, and the airlines require a health certificate from the vet but there is no quarantine. However, this is from state to state within the United States, there is the possibility that regulations would be more strict internationally although I can hardly believe it would be true when the cat originates in England where the quarantine laws are so stringent. Contact the airline first, they usually know the requirements for travel with an animal, and also google for health certificate, cat, flying, California and see what you get.
Each state could have a different requirement but you could probably google it by searching for something like animal ordinances california or rabies vaccination california. You will also need to check if there is a quarantine period. That is typically required for live animals and plants to ensure non-native parasites are not being introduced.