Beleaguered carrier British Airways was hit by a 14.9% drop in first- and business-class passengers in June compared to the same month last year.
Overall the airline carried almost 5% fewer passengers last month than in June 2008, its latest figures revealed.
A total of 2.93 million people travelled on BA scheduled services in June 2009 - a 4.9% fall on the same month last year.
Passenger numbers in Europe fell 4.3%, but this decline was dwarfed by the 16.8% drop-off in Asia Pacific traffic.
But most alarming is the ongoing slump in premium traffic - a decline that contributed to a £401m loss for the last year.
BA said: "Market conditions continue to be very challenging with trading at levels well below last year.
"However on an underlying basis both premium and non-premium volumes and seat factors have now been stable for more than three months."
The airline cut the equivalent of 2,500 full-time positions between June 2008 and March this year, and is looking to cut 3,700 more in 2009/10.
It announced last month that 2,000 of those posts would be slashed from its cabin crew.
Earlier this week it called in conciliation group Acas to help it in pay negotiations with unions.
It is feared that BA staff will strike next month if a deal cannot be agreed.
Meanwhile, low-fare airline Ryanair announced today that it carried 5.84 million passengers in June 2009 - a 13% increase on its June 2008 total.
Ryanair planes flew 85% full last month compared with 84% full in June 2008.