Airline spokesman Zhang Wuan said it still needed to wait for formal approval from the CSRC before starting its roadshow. "We hope to list within this year at the earliest," he said.

Spring Airlines, the mainland's first and largest low-cost carrier, had 46 single-aisle Airbus A320s and would take delivery of 10 more next year, Zhang said.

"We plan to add capacity on international routes because of the opening of Shanghai's Disneyland next year, which will attract tourists," he said.

The airline flies to 86 mainland destinations and 24 elsewhere in Asia, including Singapore, Osaka and Hong Kong.

The company reported a net profit of 730 million yuan for last year, compared with 620 million yuan in 2012 and 480 million yuan in 2011. Government subsidies accounted for more than 50 per cent of net profit each year.

"Strip the subsidies away, then it is not doing as good as it appears to be," said Li Xiaolu, a Shanghai-based analyst with Capital Securities. "The most important thing for low-cost carriers is to find ways to cut costs, and I think the outlook for Spring is challenging."

The airline was founded in 2004 by Shanghai businessman Wang Zhenghua to provide charter services for his Spring International Travel Agency. It became one of the first three privately owned airlines approved by the Civil Aviation Administration of China in 2005.

Analysts say the business contribution from the carrier's mother ship is a unique strength of its business model. "The travel agency provides steady traffic and good buffering," Li said.

Zhang said Spring Airlines boasted an average passenger load factor as high as 95 per cent. "I have never seen any other carrier with a higher passenger load factor," he said, adding that Spring Travel tour groups accounted for about 15 per cent of the traffic.

Spring Airlines submitted its listing application in January 2011 but ran into a 14-month listing freeze that only ended at the beginning of this year.

A scheduled assessment of the listing application in May was cancelled at the last minute because of allegations of related transactions with Spring Travel.

Zhang said the company had submitted additional documents to meet the regulator's requirements.

An industry source said it had also taken Spring Airlines so long to gain approval because it was the first non-state-owned airline to seek a listing.

"It is not easy to list as a private airline," he said. "You need to pull the right strings and Spring did not do enough of that before."

The four listed airlines on the mainland, Air China, China Southern Airlines, China Eastern Airlines Corp and Hainan Airlines, are either state-owned or partially held by local government.