Air New Zealand and Jetstar will continue to fly their normal schedules for the next 48 hours so Kiwis who were away from home when New Zealand's lockdown was announced can get home.
Travel is severely limited under level four - but air travel can be used by people travelling home in the first 48 hours after the alert level change.
New Zealand will be plunged into lockdown from 11.59pm tonight for three days - except for Auckland and Coromandel, which will stay at the country's highest alert level for seven days.
It came after a community case of Covid-19 was announced in Auckland - 58-year-old Devonport man, who had visited Coromandel with his wife over the weekend.
Air New Zealand and Jetstar said they would continue to operate their current schedule around the country for the next 48 hours.
A number of changes had been made to their services, including suspending food and drink services on domestic flights.
Water would be available on request on all flights for both airlines.
All Air New Zealand lounges would be closed from tonight.
Valet parking would be closed to new bookings, however will stay open for 48 hours for customers to retrieve their vehicle.
Frontline Air New Zealand staff would don masks and gloves and customers were still required to wear face coverings onboard.
The airline's chief executive officer Greg Foran said the airline was prepared for this scenario.
"We want to remind customers that we've been here before and have built capability to work through the changes.
"Our teams will be working hard over the next 48 hours to get Kiwis to where they need to be and we ask that customers please be patient appreciate our staff are doing their very best."
Jetstar customers with bookings to and from Auckland, Christchurch and Wellington can move their travel dates to a flight operating before 19 August at no additional cost.
Air New Zealand customers with existing bookings for travel between August 17 and August 24 would be able change their booking with change fees and any fare difference waived through to August 31.
Customers could do this via Air New Zealand's online booking tool while those who had booked through a third party would need to contact their agent.
People who had a ticket for a domestic flight departing up to September 30 could opt-in for a credit using the airline's online booking tool.
The airline noted its contact centre and social media teams were experiencing very high demand.