Global airline earnings are set to suffer their first annual decline in six years after reaching a record in 2016 as higher oil prices clip margins, according to the industry's main trade group.

Net income is likely to total $29.8 billion worldwide in 2017, the International Air Transport Association said in a statement Thursday. That's 16 percent lower than the $35.6 billion forecast for this year, a figure that itself represents a downward revision from the $39.4 billion estimated in June.

The decline would be the first since 2011, when high fuel prices and disruption caused by the Arab Spring political protests and a devastating earthquake and tsunami in Japan led earnings to fall by half.