Beijing Capital International Airport and Shanghai Pudong International Airport top the June global rankings for late flights, according to the US aviation information website FlightStats.

The survey covered 35 airports worldwide. With flight punctuality rates of only 18.3 percent and 28.72 percent in June respectively, Beijing Capital International Airport and Shanghai Pudong International Airport had the most delayed flights and their ratings changed little from January to June this year.

Similar statistics from the Civil Aviation Administration of China showed the nation's flight punctuality reached a five-year low of 74.83 percent last year.

China Eastern Airlines transported nearly 70 million passengers last year, and a single minute delay means more than 1,000 yuan ($163) in increased costs, Liu Shaoyong, president of China Eastern, was quoted as saying by Beijing News.

Su Ling, an official from CAAC, said China's civil aviation can only use 20 percent of the airspace, and the other 80 percent is for military use. Airspace in the US is 85 to 90 percent open to civil aviation.