If you want to take your pet on an Air China flight out of Beijing, then you must apply with proof of your pet's health and book the tickets three days in advance in the main Air China ticket office. 

Until this new regulation, passengers with pets could present the animal's quarantine certificates as little as four hours before boarding.

A special pressurized cabin with enough air for Fido should be booked at least one day ahead of departure.

(CRI.com June 7, 2004)