She claimed the feedback was abusive, that she was prevented from leaving the plane and that she was feeling unwell and should have been given medical treatment.
After the incident she went on stress-related sick leave for more than a month.
During that time she refused to see a company doctor and did not attend meetings with managers about her conduct on the flight.
However Ms Kilpatrick crewed on another flight to San Francisco without being cleared to return to work.
In July she was fired on the grounds of serious misconduct, which included shouting at staff in the hearing of passengers, failing to follow instructions and policies, not cooking sufficient food on the flight, and speaking to a passenger unprofessionally.
The ERA determined the feedback given after the flight in March was justified, and that while the encounter was upsetting for Ms Kilpatrick, her response was not reasonable.
Her dismissal was also justified, and Air New Zealand had acted appropriately and met its obligations as an employer, the ERA said.