The number of people taking flights in September fell by 2.9 percent compared to the same month last year, according to figures from the International Air Transport Association (IATA).
The high cost of fuel and the effects of the global credit crunch have been blamed for the first decrease in global passenger traffic since the Sars outbreak in 2003.
Commenting on the drop, Giovanni Bisignani, IATA's director general and chief executive officer said the figures revealed an "alarmingly fast-paced" decline.
"Even the good news that the oil price has fallen to half its July peak is not enough to offset the impact of the drop in demand," he said.
Latin America was the only world region to show a rise in passengers, with its carriers enjoying an increase in turnover of 1.7 percent.
Despite the figures, cheap flights carriers in the UK are remaining optimistic, with Ryanair chief executive Michael O'Leary announcing earlier this month that the credit crunch would be "good for business".