Global passenger demand in the airline industry in November was "solid but moderating," increasing by 6.2 percent from the preceding month, the International Air Transport Association (IATA) said Wednesday.

However, the November increase in revenue passenger kilometers was a slight deceleration from 6.3 percent growth in October said IATA.

Capacity, or available seat kilometers, increased by 6.8 percent over a year earlier the year-ago period, and load factor dipped 0.4 percentage point to 80.0 percent.

IATA said it was only the third time in two years that load factor fell on a year-to-year basis.

"Traffic is solid. But there are clear signs that growth is moderating in line with the slowing global economy," said Alexandre de Juniac, IATA's Director General and CEO.

IATA expects 6 percent demand growth this year, said de Juniac.

He noted, however, "Trade tensions, protective tariffs, and Brexit are all uncertainties that overhang the industry."

European carriers saw demand increase by 9.0 percent in November, a nine-month high.

Given the mixed signs on the economic backdrop in the region, it is unclear whether this pace of growth can hold, said IATA.

Asia-Pacific airlines' November traffic rose by 6.0 percent compared to a year earlier, up from 5.7 percent growth in October.

North American airlines' traffic increased by 6.1 percent in November, up from 5.7 percent in October and well ahead of the five-year average rate of 4.0 percent.

Demand increase in the Middle East carriers lifted by 2.8 percent, the lowest among the regions for a third straight month.

African airlines had a 5.7 percent rise in demand compared to November 2017, down from 6.4 percent in October but higher than the five-year average of 5.8 percent, despite challenges in the continent's largest economies, Nigeria and South Africa, said IATA.