The Chinese government warns of major flight delays at Shanghai International Airport and about a dozen other airports starting on Tuesday.
Beijing on Sunday said military exercises would cause major flight delays beginning this week until sometime in mid-August.
Media reports in China claim hundreds of flights were delayed last week at Shanghai's two airports, Pudong and Hongqiao, because of military operations. The Shanghai Daily reported around 170 flights were delayed last Thursday alone.
China says military operations are the cause of very few of the flight delays this month. It places most of the blame on bad weather.
The Chinese military controls so much of the airspace that flight delays are often a problem in the country.
The government said it will open up more airspace for commercial flights during its military exercises to help alleviate air the congestion.