Total combined international premium and economy passenger traffic grew 3.7% in the first half, identical to 2013’s first-half growth rate, according to IATA’s June Premium Traffic Monitor. June’s combined international passenger traffic growth was 2.4%, a 1.6 point drop year-over-year, and a 2.4 point slide from May.

Premium passenger traffic worldwide grew by just 1.8% year-over-year in June—down 2.3 points from June 2013 and far below May’s 6.5% growth performance, while global economy passenger travel increased 2.5% year-over-year in June, down from May’s 4.6% growth, and a 1.5 point drop from June 2013.

“This slowdown has been developing for a number of months,” IATA said. “Although international air travel was 3.7% higher [year-over-year] in the first half … passenger numbers rose by only 0.7% between December and June … the recent slowdown has been partly hidden in the year-on-year growth rate during January to May by the carry-over effect from the strong end to 2013.”

During the first half of 2014, growth in international traffic was seen most strongly on Middle East-Far East routes (up 9.3% year-over-year), Europe-Middle East routes (up 8.9%), North America-Central America routes (up 8.8%), routes within North America (up 7.6%) and North and Mid-Pacific routes (up 7.4%). Traffic on routes within South America and Africa-Far East took the biggest hits during the first half, decreasing 3.8% and 3%, respectively.

Strong premium traffic growth in June occurred largely on North America-Central America routes (up 9.7% year-over-year), Mid Atlantic routes (up 9%) and routes within North America (up 7.1%). Premium traffic fell most sharply for the month on routes within South America (down 9%), routes within the Far East (down 5.4%) and South Pacific routes (down 4.2%).

Economy traffic on routes within North America surged in June, up 11.7% year-over-year. North America-Central America routes and Mid Atlantic routes also had good showings in June, with economy traffic up 9.3% and 8.2%, respectively. Declines in economy traffic were most prominent on Africa-Far East routes (down 6.5%), Africa-Middle East routes (down 5.9%) and routes within Africa (down 4.2%).

“The problem of the moment is the relative weakness of some key emerging economies,” IATA said. “In Latin America, the Brazilian economy has been weak and is getting weaker ... [and] the economic crises in Argentina and Venezuela are also not helping. Russia is virtually in recession and travel is additionally being damaged by the geopolitical situation … the Ebola outbreak has yet to impact the data on African markets … however, travel has been discouraged by political unrest in parts of North Africa.”

Nonetheless, IATA pointed to a recent rise in business confidence indicated by the latest PMI index. “If this improvement continues, which is the consensus view now, then we would expect international air travel growth to accelerate during the second half of the year,” IATA said.