With oil prices at record high levels, Singapore Airlines said its fuel-hedging programme contributed to a better-than-expected first-half profit of S$616 million, compared with a S$6.5 million loss for the same period last year because of Sars. (US$1=S$1.67).   Group turnover reached S$5.78 billion, up from S$4.17 billion last year and S$5.3 billion in 2002….