SINGAPORE: National carrier Singapore Airlines (SIA) said on Monday (Nov 4) it will spend S$1.1 billion (US$835 million) to retrofit the cabins of its long-range Airbus A350-900 planes, as competition toughens. Cash-rich Gulf carriers like Qatar Airways and Emirates have given the industry leader a run for its money, closing the gap and even surpassing it in first and business classes, according to an analyst. SIA said in a statement that polishing up all cabin classes in 41 of its A350-900