Other factors leading to the late departure included ''significant disruptions'' through the day due to snow and ice.
The aircraft had been delayed leaving Queenstown earlier in the day because it needed to be de-iced.
"This had a knock-on effect to the aircraft's schedule and it arrived back in Queenstown 30 minutes later than originally scheduled,'' Mr Clay said.
The late arrival impacted on preparations for the aircraft's final departure, which included de-icing before take-off clearance could be given.
There was also a small delay disconnecting the aircraft from the tug unit.
Mr Clay said the pilot and flight controllers then took other precautionary steps to ensure late departure was approved - that added further delays.
By that time the 99 passengers had been on board for more than an hour.
"A number of the decision makers in the airport operations team had the welfare of passengers at heart in authorising the plane to depart too close to the close-off time of 10pm, resulting in a late departure.
Airport chief executive Colin Keel said while the late departure was not a safety issue, the airport appreciated the noise it made was ''unacceptable'' for residents who were disturbed.
"Our team had the welfare of passengers at heart, but we also have a commitment to the council and our community not to create noise outside of our consented operating hours.
"We've identified a number of corrective actions that we need to take, which are in the process of being implemented with the airlines and the airport's operations and Air Traffic Control team to ensure everyone is clear and aligned about the correct procedures,'' Mr Keel said.
