Asiana Airlines Inc., South Korea's second-largest carrier, said Thursday it posted a net loss of 46.6 billion won (US$45.3 million) in the first quarter, mainly due to a drop in passenger traffic from Japan. Operating profit also stood in minus territory at 2.1 billion won, with sales dipping 0.4 percent to 1.41 trillion won from 1.42 trillion won tallied a year earlier, the company said in a regulatory filing.