The International Air Transport Association (IATA) has released figures showing international passenger traffic has slowed for the third consecutive month.
IATA Director General Giovanni Bisignani says the industry has been hit by rising oil prices and weaker economies.
"The impact of skyrocketing oil prices and weaker economies has made its way to traffic growth."
"At this time last year we were talking about 6.7 percent growth for the first four months of the year. This year it's four percent. There has been a step change downwards."
Passenger traffic, measured in revenue passenger kilometres, rose just 3.0 percent in April, while average load factors fell to 75.4 percent, from 76.9 percent last year.
By Elizabeth Clifford-Marsh
