The latest speed-up on mainland China's railways has cut the time it takes to travel between major cities by 20 to 30 percent. But while that may be good news for passengers, airlines are worried.

Faster trains pose a bigger threat to short- and medium-haul flights. It only takes an hour to fly from Beijing to Shenyang. But most airports are located on the outskirts, so travel time between the two city centers is practically the same as the train, which is now down to 4 hours. And it costs more to fly.

Tan Zhihong, party chief of Air China said:"The rail speed increase will inevitably affect the performance of airlines. The competition will be fierce over journeys of about one thousand kilometers with flight times of an hour and a half."

However, Air China is not planning to cut short- and medium-haul flights. In contrast, the airline plans to increase flights on some routes, and streamline check-in procedures hoping to cut the journey time and make it more convenient.