China Southern Airlines (ZNH.NYSE, 600029.SH, 1055.HK) posted a net profit of US$309 million for the first six months of 2010, up from US$5.6 million a year ago, Bloomberg reported. The sharp jump was caused by a revival in air travel and by China Southern selling its stake in MTU Maintenance Zhuhai to its parent company for US$235 million. The carrier and its major domestic rivals, Air China (AIRC.LSE, 601111.SH, 0753.HK) and China Eastern Airlines (CEA.NYSE, 600115.SH, 0670.HK), saw passenger numbers rise at least 17% in the first half as the country’s robust economic growth boosted demand for leisure and business travel. China Southern said sales for the period rose 39% to US$5.1 billion. It carried 36.2 million passengers and filled 77.9% of available seats, up 3.1 percentage points from a year ago. Shares in China Southern have risen 59% so far this year.