There are unprecedented disruptions for parts of New Zealand's air traffic services, which are causing delays for passengers and costing airlines more in fuel.
The main problem area is Napier, where the air traffic control tower has been intermittently unmanned for more than a month.
But flights coming into and out of New Zealand's biggest centre, Auckland, are also facing issues.
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"As an air traffic controller and as the general manager of air traffic services, I have not seen this level of disruption before," air traffic services general manager Tim Boyle told Newshub.
It's all due to staff being sick and others undergoing training. Serious staff shortages have been an issue since early December.
"For me it's personally disappointing but we are working to address it as quickly as we possibly can," Mr Boyle said.
Asked if there hasn't been enough preparation going into staffing, Mr Boyle said, "No, it doesn't mean that at all."
Newshub understands part of the issue in Napier is because a senior controller was recently stood down from duties.
It's understood that came about after police had to evict his wife from the tower, after she arrived angry at her husband.
"I'm not going to comment on individual circumstances," Mr Boyle said.
He says Napier is being monitored remotely and isn't a safety issue, but pilots don't agree.
"It's far safer for aircraft to be in controlled airspace with a manned air traffic control service, whether it be a tower or a radar centre," Airline Pilots Association president Tim Robinson told Newshub.
Passengers Newshub spoke to on Thursday talked of delays, including those on a plane on Wednesday that ended up circling the airfield.
"I saw that we'd flown around in a complete circle, having flown regularly," said passenger Ross Boyce.
"I wondered what the problem was and someone on the aircraft mentioned there was trouble at the tower."
There have also been issues over lack of staff covering the Raglan Air Sector - the key linking pathway into Auckland.
On Monday, this area had no coverage for an hour. Up to 20 planes were affected.
As an example, on January 4, NZ628 from Queenstown should have gone straight to Auckland. But as Raglan Sector didn't have staff, the plane had to head out over Tauranga before arriving in Auckland.
"We have seen some delays that are attributable to things like pilots waiting for other aircraft," Mr Boyle said.
"That wouldn't happen under normal operation."
Air New Zealand says dealing with airspace restrictions is "not unusual" and "in these cases they may carry extra fuel".
"It is serious and it's serious in the sense that it seems to be ongoing," Mr Robinson said.
Airways, New Zealand's air navigation service provider, say their contingency operations - including that in place for Napier - are approved by the Civil Aviation Authority (CAA).
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