World airlines are expected to post a net profit of $6.9 billion this year as stronger passenger numbers offset the impact of the weak global economy, industry group IATA said Tuesday. The new forecast by the International Air Transport Association was better than its original projection of $4.0 billion made in June. Net profit for next year is expected to weaken to $4.9 billion due to the expected deterioration of global economic conditions, IATA director general and chief executive Tony Tyler told a news conference in Singapore.