Passengers wear protective masks as they wait at Hong Kong International Airport, following the coronavirus outbreak in Hong Kong, China, February 7, 2020.

Global air travel demand is set to decline for the first time since 2009 because of the coronavirus outbreak, the International Air Transport Association said Thursday.

Pauses in corporate travel and overall slumping demand due to warnings about the rapidly spreading illness have prompted carriers to suspend service or drastically reduce China service.

The virus's impact on demand will cost airlines globally more than $29 billion — mostly in the Asia-Pacific region, IATA estimated. Chinese airlines are set to lose $12.8 billion in revenue because of the outbreak. The trade group, which represents most of the world's airlines, had forecast demand growth in 2020 of 4.1%, which it's now revised to a contraction of 0.6%.

The forecast assumes the virus remains largely concentrated in China, but IATA warned the impact could be greater if it spreads to other markets in the region.

The group based its estimates on the coronavirus having a "V-shaped impact on demand" as occurred during the 2003 SARS outbreak, which was marked by a six-month decline and "an equally quick recovery."

"These are challenging times for the global air transport industry. Stopping the spread of the virus is the top priority. Airlines are following the guidance of the World Health Organization and other public health authorities to keep passengers safe, the world connected, and the virus contained," said IATA's CEO, Alexandre de Juniac, in a release.

"Airlines are making difficult decisions to cut capacity and in some cases routes," he said. "Lower fuel costs will help offset some of the lost revenue. This will be a very tough year for airlines."