Taking China domestic flights, you would better arrive at the airport within the time limit set by the airlines. Most of the Chinese airlines stop the check-in procedures 30 minutes before departing. In some large international airport, the procedures are stopped 45 minutes or one hour before the departure. So you are suggested to reach the airport at least 1.5 hours in advance. For international flights, it is better for you to reach the airport 3 hrs before departure.