Air New Zealand has revealed details of what went wrong when it was forced to offload bags for scores of passengers on a New York-Auckland flight.
The airline - which launched the flagship route at the weekend - has now started a review to cut the chances of this happening again.
The airline says it will compensate the passengers who are out of pocket because they needed to purchase essential items due to the delayed arrival of their bags. At this stage it has not received any requests for compensation.
While bags have today been couriered via Los Angeles to 60 affected passengers on the inaugural southbound flight, some are angry at having bags left behind for more than 24 hours.
Air New Zealand has blamed the problem on a combination of factors, highlighting the challenge of flying aircraft near the peak of their range on non-stop ultra long haul routes.
Airline chief operating officer Alex Marren said the "incredibly disappointing" decision to offload 65 bags was made on Saturday when it had to amend its flight plan to go around a forecast cyclone.
The temporary closure of the usual alternative airport, Ohakea Airbase, also meant additional fuel was required in case of the need to divert from Auckland International.
"To get all of our customers where they needed to be, the team took the unusual step of offloading around 65 bags to meet the load limits," said Marren.
"Operating ultra-long-haul flights is challenging and Air New Zealand has been working towards the launch of this route for years, so it is incredibly disappointing that we weren't able to bring all of our customers' bags on Saturday's inaugural flight."
The flight time for NZ1 was 17 hours 35 mins and it is the airline's longest route, covering close to 14,200km and is the fourth longest in the world operating now.
"We made some adjustments to the number of seats sold to compensate for the extra fuel required to go such a long distance. We also do not carry cargo on the southbound leg."
Before it launched the service Air New Zealand said it would sell fewer seats on the southbound flight and this was the case on Saturday. There were 202 seats sold out of a possible 275.
"We intentionally do not sell all the seats to compensate for the extra fuel load required for the ultra-long haul flight," said Marren.
She said the airline was sorry it wasn't ''plain sailing'' for all the passengers on the flight.
"This is not the way we wanted things to run for our customers and we'll be reviewing what lessons we can take to make sure this doesn't happen again," said Marren.
One Hamilton-based passenger and her husband were among the passengers left waiting for an hour to be told that their luggage had been left behind.
"We had to be told by a fellow passenger that our bags were not on the flight," she said yesterday.
Returning from a 10-day holiday to the US they said there were issues checking in luggage and finding tickets at JFK, which was at odds with the hype around the inaugural service, the Herald reported yesterday.
"We were greeted at Auckland by media celebrating the success of the route, however, things were a shambles outside of the flight itself."
While bags are being sent on to passengers, airlines are liable if they are lost or delayed.
Consumer NZ's Jessica Walker said international flight luggage is covered by the Montreal Convention. The convention sets out the maximum amount an airline has to pay for lost, damaged or delayed bags. The sum is about $2700 per passenger.
"If bags are delayed the airline only has to cover the cost of essential items. Typically, airlines don't accept liability for consequential losses. For delayed bags you have to claim within 21 days from the date you should have received them," she said.
"If you have travel insurance, check your policy as it may also offer greater protection and coverage than the law."
Air New Zealand says it will be contacting them individually to offer an ''additional goodwill gesture'' for the inconvenience caused by this week's baggage disruption.
Cyclones over the Caribbean and Alaska have been hitting opposite corners of the United States during the past week.
John Murrie, from Massey University's School of Aviation, said the constant jetstream winds that blow from west to east were also a factor. They provide a tailwind for eastbound flights such as NZ2 into New York, making it an hour or more quicker.
There was a reasonably strong jet stream across the western and northern United States over the period the flight was heading to and from New York.
That jet stream - a "river" of fast-moving air at altitudes passenger jets operate - started just west of California, headed over the state, and then swung north toward the Canadian border before heading east again.
Flight data shows NZ1 reaching an altitude of 42,000 feet close to New Zealand before descending into Auckland.
The airline has 787-Dreamliners on order with a heavier premium skew, fewer seats overall and better equipped to cover the distance to US eastern seaboard routes. However, they are not expected to join the fleet until 2025.
The airline sold its last slots at Heathrow in 2020.