Malaysia's flagship budget airline AirAsia Group Bhd flipped to a loss in its third-quarter, hit by foreign exchange losses and a writedown in the value of currency and interest rate swaps.

It posted on Wednesday a net loss of 51.4 million ringgit ($12.3 million) for the three-month period ended September, from 915.9 million ringgit net profit in the year ago period. Revenue was 17.5 percent higher at 3.1 billion ringgit, however.

In a filing to the bourse, it also recorded a depreciation of right of use of asset, and finance costs for lease liabilities during the quarter. Among its non-airline businesses, travel and lifestyle arm AirAsia.com and financial services unit BigPay also recorded wider losses.

Cost per unit during the period rose 11 percent mainly due to increases in maintenance and overhaul, user charges and other operating expenses. AirAsia recorded one-off gains in the corresponding period last year from the disposal of its remaining stake in a joint venture with travel platform Expedia Group Inc for $60 million, and a 515.4 million ringgit deferred tax asset linked to aircraft disposals during the quarter.

The airline carried 13 million passengers in the three months, 20 percent higher but load factor - which measures how full planes are - fell 2 percentage points to 84 percent. The group said it was positive about ts fourth quarter performance, a seasonally strong period. It is also planning a net fleet growth of 18 aircraft, it said.