Cho was also convicted of assault on the cabin crew.
The chief steward, Park Chang-Jin, had testified that Cho had made him kneel and beg for forgiveness while jabbing him with a service manual.
Prosecutors in the trial had asked for a three-year sentence, but Mr Oh said he had taken into account that no lives had been jeopardised in the incident, as well as the fact that Cho had two young children and that her personal and professional reputation had been shattered.
Dismissing defence arguments to the contrary, the court ruled that an aircraft should be deemed “in flight” from the moment it begins to move and that Cho was therefore guilty of illegally altering the course of a plane.
She was acquitted of obstruction of justice charges related to allegations that she had pressured KAL staff to lie about the incident.
Another defendant, also a KAL executive was convicted of forcing the flight crew to give false testimony and was jailed for eight months.
Although Cho had submitted letters to the court expressing repentance for her behaviour, Mr Oh questioned whether she was truly remorseful.