The effects of Superstorm Sandy which devastated parts of the Northeastern US and the Carribean last month are deepening an already dire situation for the global airline industry, the International Air Transport Association (IATA) said. The massive hurricane \"dealth the airline industry a $ 500-million (385-million-euro) blow at a time when it can least afford it,\" IATA chief Tony Tyler said in a statement. The organisation calculated that nearly 17,000 flights were cancelled to the five US airports most affected by the storm, John F. Kennedy, Newark and LaGuardia in New York, as well as the Washington-Dulles and Philadelphia airports. \"At the peak of the storm on Monday, October 29, 8.0-9.0 percent of global capacity was grounded,\" IATA said, stressing that this was equivalent to 1.6 billion available seat kilometers. \"Hurricane Sandy delivered a concentrated punch to US domestic and North Atlantic travel. And its impact was felt globally,\" the organisation said. It pointed out that the storm had exacerbated already weak air travel demand due to \"slowing world trade and weak business confidence.\" All in all, passenger demand had risen 2.8 percent last month compared to October 2011, but had fallen 0.5 percent compared to September, IATA said. At the same time, though, freight demand slipped 3.5 percent year-on-year and 2.2 percent compared to September. \"Airlines are managing the softer passenger demand environment by limiting capacity growth to keep load factors high,\" it said, pointing out though that \"the rapid decline in freight traffic is outrunning the industry\'s ability to respond.\" Hurricane Sandy had hit the US domestic market the hardest, IATA said, pointing out that around two thirds of all air passengers impacted by Sandy were traveling internally in the US. US domestic traffic thus slipped 0.7 percent year-on-year in October, while capacity fell 1.1 percent. This in turn pushed the load factor up to 84 percent — the highest among all domestic markets, IATA said. Demand in that market fell 1.1 percent compared to September, it said. North American airlines\' international traffic numbers had meanwhile inched up 0.2 percent from October a year ago, but Sandy has sent seat capacity down 2.2 percent year-on-year, with demand declining 0.9 percent compared to September, it said. European carriers were also hit by the hurricane, showing a 1.6-percent drop in international traffic compared to September as \"Sandy negatively impacted transatlantic travel.\" Compared to October a year ago, however, European airlines saw their international services grow 2.6 percent.