Thailand-based low-cost carrier (LCC) Nok Air reported first-quarter net loss of THB379.9 million ($10.8 million), reversed from net profit of THB55.6 million in the year-ago period.

First-quarter revenue fell 2.04% to THB3.38 billion; operating costs for the quarter were THB3.55 billion, up 10.8% from the year-ago period.

The LCC attributed increased costs to the rise of aircraft lease rental and ongoing maintenance costs from a recent fleet expansion. Additional pressure came from “domestic low-cost carriers still facing challenges from [local] price wars and oversupply.”

The company also said the lower-than-expected results, and the revenue decrease, were “mainly due to flight frequency cuts [resulting in] a 7.1% decrease in ASKs and a 10.3% drop in the number of passengers carried as a result of the reduction in pilots [numbers].” The carrier experienced significant flight disruptions in February as a result of new working conditions leading to a pilot strike.

First-quarter RASK increased to THB2.27, up 2.25% year-over-year (YOY), but mainly because of a reduction in seat availability, the airline said. First-quarter CASK was THB2.57, up 17.4% YOY. However, international scheduled and charter flight revenue for the quarter grew 228.2% YOY in line with the carrier’s plan to develop more revenue from international routes. Overall first-quarter passenger yield was THB2.34, down 2.9% from the same period last year.