Cho, 40, did not answer questions from reporters as she left the court surrounded by Korean Air employees and after she changed into personal clothes from her prison uniform. She was driven away in a black car.
Prosecutors were not immediately available for comment on whether they would appeal the ruling.
The court upheld Cho's conviction, finding her guilty of breaking South Korea's aviation law, but reduced her sentence to 10 months, which it suspended. It noted her previous lack of a criminal record and that she is the mother of young twins.
"The defendant would have had a chance to reflect sincerely on the mental anguish she caused in the victims during the five months she spent in the darkest place in society while in detention and away from family," Judge Kim Sang-hwan said.
Cho's lawyer did not say if Cho would appeal her conviction.
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A lower court ruled in February that the airline's former vice president and head of in-flight service had violated the law by ordering the plane to return to its gate.
Cho faces a civil suit filed in New York by a flight attendant involved in the incident for damage caused to her career, reputation and emotional health, seeking unspecified damages.
Cho resigned from all posts at the airline after the incident became public. Her outburst began when she was served macadamia nuts in a bag, not a dish, while seated in the first class cabin of the A380 jumbo jet.
She is the oldest of Korean Air chairman Cho Yang-ho's three children. Her siblings are executives with the airline.