China's first budget carrier, Spring Airlines, doubled its net income in the first half of this year and plans an initial public offering next year to fund fleet expansion.

The Shanghai-based carrier earned 160 million yuan (US$23.6 million) in the first half, compared with 41.17 million yuan a year earlier, and its revenue jumped 60 percent to 1.47 billion yuan, the company said at a ceremony to mark its fifth anniversary yesterday.

Spring Air has been profitable since its launch in 2005 and covers more than 50 domestic routes with a fleet of 20 A320 jets.

The carrier attributed the positive results to costs being significantly lower than its domestic rivals.

Spokesman Zhang Wuan said Spring Air planned to expand its fleet size to 100 aircraft by 2015. The carrier is on the track to launch an IPO on the Chinese mainland next year to fund its fleet expansion, Zhang said.

The carrier plans to launch its first international route on July 28. A320s will service the route between Shanghai and Ibaraki Airport, about 80 kilometers from Tokyo.