Air New Zealand is bracing itself for the possibility of further strikes, on top of one planned for the busiest travel day of the year.
The holiday plans of tens of thousands of people are up in the air, with airline staff threatening to strike on 21 December over pay and working conditions.
The strike would affect up 42,000 international and domestic customers who were booked to travel that day.
"I'm just refreshing pages to find out what's actually happening and whether it's going to go ahead," said Lauren White, who was booked to travel from Tauranga to Christchurch on the day of the strike.
"If it's not going to go ahead then great news, I'm going to relax. But until then, it's kind of a nervous wait."
Ms White said she supported workers' right to strike, but said the timing was far from ideal.
In Sydney, JoJo Warren was anxious to make it home for her first Christmas since moving away from family.
"Just really worried and concerned about my flight getting cancelled, as I really just want to get home for Christmas," she said.
"What does that mean? Do they (flights) get cancelled, delayed, postponed?"
Air New Zealand landed the first blow this morning and said the striking staff were using peoples' hard-earned holidays as a bargaining chip.
In a statement, the airline said the average wage of the staff in question was $115,000 a year - with some earning more than $150,000.
Its general manager of aircraft maintenance, Viv de Beus, said the staff have had year-on-year pay increases; and engineers got six weeks of annual leave, a car park, and recently had a $6,400 one off payment.
"We know how important summer holidays are for our customers who look forward to being able to gather with friends and family at this important time of year," he said in a statement.
"It would be devastating to see the holiday plans of more than 40,000 hardworking Kiwis and international visitors ruined."
However, the unions involved are not liking Air New Zealand's tone.
E Tū union's head of aviation, Savage, said the airline was trying to mislead the public.
"Air New Zealand is trying to portray this as a group of overpaid engineers when actually there are a lot of underpaid logistics and cleaning staff also included in the collective agreement," he said.
"This is primarily about Air New Zealand making record profits and then attempting to cut the pay and conditions of their workers."
Air New Zealand, E Tū and the Aviation and Marine Engineers Association were to enter negotiations on Monday.
But the unions believed the 'greedy engineers' narrative Air New Zealand was painting undermined the upcoming mediation.
If the two sides could not strike a deal, tens of thousands of customers would have to scramble to rearrange their plans.
If it did come to that, Air New Zealand said it would get in touch with passengers closer to the time.
But it warned it might not just be customers flying on 21 December who could be affected, as it had been advised by the union to expect further industrial action.