Australia’s flagship airline, Qantas Airways Ltd (QAN.AX), is making a mint helping other companies keep their customers – even as it struggles to retain the loyalty of its own. Hiding behind Qantas’ staggering A$2.8 billion ($2.6 billion) headline annual net loss announced last week is a hugely profitable loyalty program that is the envy of the airline world – and the carrier isn’t letting go. Some investors have urged Qantas to sell all or part of Qantas Frequent Flyer, which is valued as high as A$3 billion.