Korea Air Lines former executive Heather Cho has been sentenced to one year in prison for assault and violating aviation safety law after a bizarre outburst that triggered a national scandal.

In December, the daughter of the airline’s CEO delayed a flight from New York to Seoul because her macadamia nuts had been served in a pre-packaged bag, not a dish.

Cho, who was the airline’s executive vice president at the time, forced the plane’s chief steward to kneel and beg for forgiveness for the error while jabbing him with a service manual.

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The 40-year-old had treated the flight “as if it was her own private plane”, Justice Oh Sung-Woo said, adding that the case had become the object of international ridicule and “damaged the dignity” of the country.

Korean Air CEO Cho Yang-ho apologised for his daughter’s actions. Photo: AAP

Cho treated employees “like feudal slaves” and failed to show “the slightest respect” for other people, the judge said.

“This is a case where human dignity was trampled upon.”

The defendant wiped away tears as the judge read his ruling.

In a letter of apology read out by the judge, Cho said she was “deeply sorry”.

“I displayed my anger without control,” she wrote. “I don’t know how I can ever be forgiven.”

But the judge questioned her remorse.

Prosecutors in the trial had asked for a three-year sentence, but the judge 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.

Cho was forced to resign in disgrace after her outburst became public.

Another Korea Air Lines executive received an eight-month sentence for giving false testimony.

—with AAP.