Korean Air said Monday it expects to earn 1.5 trillion won ($1.3 billion) in sales of wingtips and cargo doors by 2021 as the country’s flag carrier boosts its aircraft parts business to diversify its revenue structure.

The country’s largest airline said it delivered on Sunday the first set of its fuel-saving wingtip components, codenamed “Sharklets,” for Airbus S.A.S.’ A320 jets.

The L-shaped parts, which will replace the current wingtip fence, will help enhance the aircraft’s payload range and take-off performance while raising fuel efficiency by some 3.5 percent and saving 700 tons of emissions per plane annually, company officials said.

Korean Air won a contract in May 2010 to become the sole supplier of the devices, beating rivals from Japan, France and Germany.

“We plan to increase Sharklet output gradually and supply 600 units a year starting mid-2013, for which we’re constructing a large-scale production line in Busan,” Korean Air said in a statement.

Korean Air has been bolstering its airplane part manufacturing unit as it seeks fresh income sources in the face of spiraling oil prices, lower cargo demand and intensifying competition with budget airlines. It also supplies wing parts for U.S.-based Boeing’s B787, B777 and B747-8 models.

With full-fledged production under way, the flag carrier said it projects to make 1.5 trillion won by 2021 by selling the Sharklets and cargo doors, used for the French aerospace firm’s A350 airliners.

The cargo doors alone will bring in at least 500 billion won in revenue, the airline added.

By Shin Hyon-hee (heeshin@heraldcorp.com)