Hainan Airlines, China's fourth-largest carrier, on Wednesday posted a net profit increase of 20 per cent for last year and said it would buy 30 next-generation Boeing 787 planes for up to US$7.7 billion. The airline, which was operating 169 aircraft at the end of last year, posted net profit of 2.59 billion yuan (HK$3.27 billion) on a 14 per cent traffic increase. Passenger load factor grew by 1 percentage point to 86.8 per cent. Revenue from core business rose 4.7 per cent to 32.4 billion yuan, with an 11.92 per cent growth in business outside mainland China. The company said in a separate notice to the Shanghai stock exchange that it planned to order 30 B787-9 aircraft from Boeing, with a catalogue price of US$257 million each. The plane, known as the Dreamliner, is Boeing's new fuel-efficient long-range aircraft that seats 280 passengers. The order is expected to have a volume discount and will be for delivery before 2021. Fuel, which halved in a global oil price plunge in the second half, accounted for 39.11 per cent of Hainan Airlines' operating costs last year. Fuel price fluctuation, currency, and competition from the high-speed rail network are among the biggest risks for its operations in 2015, the firm said. In another notice, the airline said it has signed a reciprocal reinsurance agreement with its parent HNA Group to increase the credit guarantee it receives to 40 billion yuan. HNA Group, a conglomerate with businesses spanning transport, tourism and finance, counts both Hong Kong Airlines and Hong Kong Express as subsidiaries. Hainan Airlines also said it will inject 400 million yuan into Xian-based Changan Airlines, of which it is a controlling shareholder. It gained three more airline subsidiaries in the past year: it became a controlling shareholder of Kunming-based Lucky Air since March, while its subsidiaries Urumqi Airlines and Fuzhou Airlines began operation in the second half. Hainan Development Holding, a wholly owned investment arm of the Hainan government, lowered its direct ownership in Hainan Airlines to 4.89 per cent through a stake transfer in December to the controlling shareholder Grand China Air.