The nation’s low-cost carriers were estimated to have more than doubled their operating profit in the first quarter over the same period last year thanks to a diversification in their routes. 

According to aviation and securities industries and the transportation ministry on Wednesday, six low-cost airlines were tentatively estimated to have posted nearly one-point-two trillion won in sales and 186 billion won in operating profit in the first quarter. 

Compared to the same period last year, sales climbed some 34 percent and operating profit surged nearly 131 percent. 

The six carriers’ operating profit outperformed the nation’s largest airline, Korean Air. 

While another major carrier, Asiana Airlines, saw its earnings more than double in the first quarter, Korean Air witnessed its operating profit slip slightly, becoming the only domestic airline to suffer a reduction in profitability. 

The stronger won also contributed to enhancing carriers’ earnings as many of the airlines hold liabilities denominated in foreign currency.