The Korea Centers for Disease Control and Prevention (KCDC) said on Wednesday that the crewmember had been on a Korean Air KE958 flight from Israel to Incheon on Feb. 15-16. The passengers included a South Korea tour group from which 31 coronavirus cases were seen to have originated.
But it has yet to release details of other routes and flights flown by the employee.
Yonhap News Agency and other media said she worked on flights KE017 and KE012 on Feb. 19 and Feb. 20 to and from Los Angeles.
Some 30 crewmembers who were on the same flights with her have self-quarantined for 14 days, media reports said.
Korean Air has referred all inquiries about the employee's itinerary to KCDC, as the authority in charge, adding "We will continue to work closely with the relevant authorities to ensure the safety of our passengers and employees."
South Korea on Thursday reported 334 new coronavirus cases on Wednesday, pushing the total to 1,595.
Korea has the highest number of infected people outside China.
U.S. President Donald Trump assured Americans on Wednesday the risk from coronavirus remained "very low" and was not immediately considering travel restrictions to and from countries such as South Korea and Italy that are dealing with outbreaks.