Beijing's main airport was ranked lowest for on-time departures last month as military controls of airspace and an expanding fleet add to air-traffic congestion.
Shanghai was second-worst among the world's 35 busiest international airports, industry researcher FlightStats Inc. said.
Tokyo's Haneda airport was the top performer with 95 percent of flights leaving on time, followed by Narita airport.
About 18 percent of the 22,019 flights leaving Beijing Capital International Airport were on time, while Shanghai Pudong International airport had a rate of about 29 percent, FlightStats said.
FlightStats logs a delay if a plane fails to take off within 15 minutes of the scheduled gate time.
Air China Ltd., China Eastern Airlines Corp. and other carriers are expanding fleets as economic growth spurs travel demand in China, where the air force allots only 20 percent of air space to civil aviation. The congestion is set to worsen as its commercial fleet is projected to double in the next seven years.
Amsterdam airport ranked third out of the 35 facilities, with an on-time departure rate of 84 percent, while John F. Kennedy International Airport in New York was 26th at 66 percent. London Heathrow was 21st at 72 percent.
Hong Kong International Airport was 29th, with 64 percent of 12,417 flights leaving on time, FlightStats said. Singapore Changi Airport ranked 10th, with a 78 percent on-time performance.
As for arrivals, China United Airlines Co. was the worst of the 41 Asian carriers surveyed with 27 percent of flights landing on time. China Eastern was 33rd at 57 percent and China Southern 29th at 62 percent.
Asia's top-ranked carrier was Air Busan with an on-time arrival rate of 97 percent, FlightStats said.