The daughter of Korean Air's chairman was jailed for one year this morning over a now notorious on-board "nut rage" incident.

Prosecutors had demanded a three-year sentence for Cho Hyun-Ah, who was a Korean Air executive vice president at the time and was charged with violating aviation safety law, obstructing justice and assaulting a member of the cabin crew.

The charges all stemmed from an incident in which Cho forced the chief purser off a 5 December New York-Seoul KAL flight, compelling the taxiing plane to return to the gate so he could disembark.

The 40-year-old had taken exception to being served macadamia nuts she had not asked for, and in a bag, not a bowl.

The district court in Seoul ruled that Cho had illegally altered the course of the plane, judging that an aircraft was "in flight" from the moment it begins to move.

Cho had treated the flight "as if it was her own private plane", justice Oh Sung-Woo said.

"It is doubtful that the way the nuts were served was so wrong," he added.

In passing sentence, the judge indicated that Cho had failed to show enough remorse for her actions, even though she had submitted some letters to the court expressing repentance for her behaviour.

Cho, who has been in custody since her arrest on 30 December and attended the court in a green prison outfit, stood silently throughout the ruling, her head bowed.

She had pleaded not guilty to most of the charges, including physically assaulting the chief steward, Park Chang-Jin, who says she made him kneel and beg for forgiveness while jabbing him with a service manual.

The case triggered a huge public backlash.

Cho was seen as emblematic of a generation of spoilt and arrogant offspring of owners of the giant family-run conglomerates, or "chaebols," that dominate the South Korean economy.

Like Cho, many are given senior positions in the family business, sometimes after a token period "learning the trade".

In the past, chaebol owners have appeared to be above the law. Those convicted of gross fraud have either received lenient sentences or been granted pardons after just a short time in jail.

Cho resigned from all her posts and publicly apologised for her behaviour, which her father and KAL chairman Cho Yang-Ho also criticised as a "foolish act".

The story hit international headlines and Justice Oh said in his ruling that "damaged the dignity of the country".