SEOUL: Korean Air Lines posted on Thursday a consolidated operating profit of 109 billion won ($97.55 million) in 2020, as cargo sales helped offset a slump in passenger travel on the back of coronavirus restrictions.

While South Korea's largest airline managed to avoid an annual loss in 2020, operating profits were down 58% from 257 billion won in 2019, the company said in a regulatory filing.

Cargo sales jumped 66% to 4.3 trillion won in 2020 from a year earlier, while passenger sales slumped 74%. Cargo sales were underpinned by the airline's strategy to increase the operation rate of cargo planes and utilise idle passenger planes for transport, the airline said in a statement.

"Demand for COVID-19 diagnostic kits and auto parts has increased, and some sea cargo demand has transferred to air transport, driving the increase in air cargo sales," it said.

Korean Air is one of the world's biggest air cargo carriers and has benefited from strong demand at a time when the collapse of passenger traffic has reduced available transport space.

The fourth quarter, coinciding with electronic product launches and Christmas, is the peak season for air freight and rates were up strongly due to the capacity crunch and the start of vaccine transport.

Air cargo demand and freight rates remained unusually strong in January because of tight capacity, according to data provider CLIVE Data Services.

Korean Air's acquisition of Asiana Airlines Inc, announced last year, is on track and awaiting approval from antitrust authorities, a spokeswoman said on Thursday.

Shares in Korean Air closed up 1.3%, compared to a 1.4% fall in the wider market.

South Korea's President Moon Jae-in called on Wednesday for seamless preparations for coronavirus vaccinations, as regulators approved imports of Pfizer's COVID-19 shot and the country prepared to begin inoculations later this month.

Korean Air is aiding with vaccine transport.