The advantages of China's high-speed railways are becoming clear since they forced air authorities to suspend flight services between two major cities.

All flights linking Wuhan, the capital of Hubei province in Central China, and Nanjing, the capital of Jiangsu province in East China, have been suspended since March 27, according to the General Administration of Civil Aviation of China. The suspension will stay in place until September, when the air authority will re-evaluate the use of air services.

This is the first air route halted at Wuhan's airport as the city emerges as a hub of China's expanding high-speed railway network, which had a total length of 8,358 kilometers at the end of last year.

Previously, two daily flights linked Nanjing and Wuhan, about 520 km from each other, and a full price one-way ticket cost 730 yuan ($111).

The intercity bullet trains, which began service in 2009, running at up to 250 km per hour, offer second-class tickets for 180 yuan.

The high-speed trains have an occupancy rate of about 90 percent, outperforming the flights, which had an occupancy rate of less than 50 percent on workdays.

With additional bullet train services coming in the third quarter of this year, the rail system, which has drawn international attention, is expected to consolidate its advantage.

"Our flights were seriously affected after the high-speed rail lines opened," Meng Qian, deputy director of the marketing department of Lucky Air, said on Friday. The Yunnan-based budget airline was making a scheduled round trip passenger flight daily between Wuhan and Nanjing.

Meng said the flight, which had been in service for five years, had been suffering big losses since 2009.

Even after Lucky Air offered up to 80 percent discounts on tickets, the flights were less than half full on non-holidays, according to a previous report. China Southern Airlines had the same experience with flights it offered.

Peng Guohua, 53, a Wuhan resident who made regular business trips to Nanjing, said he preferred the trains because when the amount of time traveling to and from the airports was factored in, the airliners were not much faster than the three-hour trip on the bullet trains.

This is not the first time in China that high-speed rail has forced airlines to halt intercity flights.

In November 2009, flights between Chongqing and Chengdu were halted after bullet trains started running. Last year, a high-speed line linking Zhengzhou and Xi'an edged out airline competitors, stirring speculation that the growth of high-speed railways would hit airlines hard.

Ji Jialun, a professor of transportation at Beijing Jiaotong University, said on Friday that bullet trains currently have the advantage, with cheaper fairs, travel safety and increasingly higher speeds.

"Railways will play a bigger role after more high-speed lines are added to form a network," he said.

But he also said the aviation industry can find a market niche by offering long-distance trips or regional air service for more affluent passengers.

"Passengers will ultimately benefit from the competition offering more options," he said.

According to the Ministry of Railways, China will have a total of 12,000km of high-speed rail by 2012, the largest such network in the world.