Korean Air took delivery of its first Bombardier C Series CS300 jet on Friday.

With that, Korean Air became the third global airline to take delivery of the jet -- the larger of the two “C Series” models from Canadian jetmaker Bombardier. Swiss and Latvia’s airBaltic are the two other carriers already flying the CS300.

Korean Air, the Asian launch customer for the model, has configured its CS300s with 127 seats in a 2-by-3 layout. Of those, 25 will be extra-space Premium Economy seats, which debut in Korean Air’s fleet on the CS 300s. Korean Air says customers sitting in the new Premium Economy seats “will be able to enjoy a wider pitch (4 inches wider) and a wider seat width of 19 inches.”

The jet delivered Friday is the first of 10 on order by Korean Air. The second jet of the order is expected to be delivered to Korean before the end of the month.

Korean says it will use its new CS300s on “lower-density regional routes,” a move the airline says will free up its bigger single-aisle aircraft for higher-traffic routes.

ARCHIVES: Bombardier eyes lift after completing first CS300 flight (story continues below)

“We have witnessed the C Series impressive first year in service, and are pleased to take delivery of our first Bombardier CS300 aircraft,” Soo-Keun Lee, Korean Air’s Chief Technology Officer, said in a statement accompanying the delivery. “The CS300 will enable us to reinforce our regional single-aisle operations, while providing a high level of profitability and customer satisfaction. These are key drivers of our decision to acquire the Bombardier CS300, and we are looking forward integrating it to our fleet.”

Korean says the first CS300 will arrive in Seoul on Dec. 25 and will begin operating on its domestic routes starting Jan. 16.

For Bombardier, the delivery is the latest sign of progress in its troubled C Series line. Sales of have been slow for both the CS300 and the smaller CS100 model.

Bombardier received a shot in the arm for its CS100 in 2016, when Delta made a firm order for 75 of the jets. But that led to Boeing filing a trade complaint alleging that Bombardier was dumping the planes in the U.S. market below cost.

A trade spat has since ensued, with the U.S. tentatively threatening a tariff of nearly 300% on CSeries aircraft. The dispute has ratcheted up recently, with Canada nixing a Boeing fighter-jet order and Bombardier announcing that it had sold a majority stake in its CSeries line to Boeing archrival Airbus. As part of the latter, Airbus would assemble CSeries jets bound for U.S. airlines at its new factory in Alabama.

MORE: Korean Air shows off new Boeing Dreamliner in South Carolina