Fitch said it was annoying that it was not only first time it had happened, but that nobody is made accountable.
"Napier Airport is probably one of the bigger regional airports in New Zealand, so for it to have so many issues with staffing its control tower will have a big impact for others and their flights if this keeps going on.
"But the worst thing is that no one is footing the blame, if I did that where I worked and had understaffed areas and things weren't able to operate properly I would probably get the sack."
External communications specialist at Airways New Zealand Emma Lee said in a statement that "contingency procedures" were in place for Napier's air traffic control tower on Saturday and Sunday, from 12pm to 6pm, due to a lack of staff.
"When contingency procedures are in place, the number of aircraft able to fly in the airspace surrounding the airport is restricted and pilots use standard visual separation rules to stay safely separated.
"Air traffic controllers based in our radar centre in Christchurch continue to monitor the aircraft once it reaches airspace covered by radar."
Napier has recently experienced an unprecedented staffing shortage, with three of five controllers unavailable for work.
Seconded controllers have been brought in to support operations at Napier tower until permanent staff are able to return to the roster, Lee said.
"Normal staffing levels were expected to be restored at the tower in March, however, permanent staff have been unable to return to work in the timeframe expected.
"Newly qualified controllers are expected to begin work at Napier at the end of the April.
"We anticipate some level of contingency cover will continue to be required throughout April to accommodate staff sickness and any other unexpected absences."
Fitch said that although it was not the fault of Air New Zealand, the airline had been having to take most of the slack from irate travellers.
"They were very helpful in getting them on to another flight and from what I could see they seemed to get a lot of stick from passengers and will be getting a bad rap from passengers when it isn't their fault."
Air New Zealand said it did not want to comment on the issue.