The effects of Superstorm Sandy which devastated parts of the Northeastern US and the Caribbean last month are deepening an already dire situation for the global airline industry, the International Air Transport Association (IATA) said on Thursday.

The massive hurricane "dealt 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 kilometres.

"Hurricane Sandy delivered a concentrated punch to US domestic and North Atlantic travel. And its impact was felt globally," the organisation said.

Tyler pointed out that "direct flight cancellations reached airports as far apart as Singapore, Johannesburg and Santiago."

"Meetings were cancelled, shipments delayed, conferences postponed and supply chains disrupted," he said, pointing out that "the disruption ... demonstrated just how connected the aviation industry has made the world."

IATA pointed out that the storm had exacerbated already weak air travel demand due to "slowing world trade and weak business confidence."

Globally, 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 travelling internally in the United States.

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.

While Europe thereby saw the highest growth among the major regions, its October numbers were a far cry from the 5.5-percent year-on-year growth recorded in September.

Asia-Pacific carriers meanwhile saw only a 1.4-percent hike traffic last month compared to October 2011, and IATA speculated the weak growth could be due to "strong competition on long haul markets."

India, which showed the worst performance for any market with its domestic traffic plunging 12.4 percent, probably also impacted the overall Asia-Pacific numbers, the organisation said.

The strongest hike last month was meanwhile seen by Middle Eastern carriers, which saw a 12.4-percent rise in international traffic compared to October 2011, followed by Latin American airlines, which posted 6.8-percent growth.

According to IATA, around 57 million globally work in the air transport industry, which "supports $2.2 trillion in economic activity by connecting people and goods on 35,000 routes."