Cho Hyun-ah, also known as Heather Cho, daughter of chairman of Korean Air Lines, Cho Yang-ho, appears in front of the media outside the offices of the Aviation and Railway Accident Investigation Board of the Ministry of Land, Infrastructure, Transport, in Seoul December 12, 2014. [Photo/Agencies]

The lower court had convicted Cho of forcing a flight to change its route, obstructing the flight's captain in the performance of his duties, forcing a crew member off a plane and assaulting a crew member. It found her not guilty of interfering with a transport ministry investigation into the incident. Cho pleaded not guilty and prosecutors had called for three years in prison.

The aviation security law is meant to regulate highly dangerous acts such as hijacking. But the upper court said Friday that there wasn't a big safety threat posed by Cho's actions, and returning the plane that was taxiing did not constitute forcing a change in the plane's route.

Kim Sang-hwan, head of the three judge upper court panel, said that even though Cho used violence against crew members, she should be given a second chance. The judge also cited her "internal change" since she began serving her prison term as a reason for lessening the sentence.

The upper court also took into consideration that Cho is the mother of 2-year-old twins and had never committed any offense before. She has resigned from her position at the airline.

"It appears that she will have to live under heavy criticism from society and stigma," said Kim.