Kiwis love to fly, with most not thinking twice about an OE, a trip across the ditch or a round-trip between Auckland and the capital for a face-to-face.
But climate change and "flight shaming" may have some feeling a bit guilty - and also wondering where that "carbon offset fee" they accepted while booking their ticket actually goes.
'Flight shaming" has come from the Swedish movement of "Flygskam", which started last year, and it involves urging people to reconsider whether they really need to fly.
Air travel contributes about three per cent of the world's carbon emissions each year, with 4.6 billion people taking a flight in 2019, and the industry is growing by up to five per cent each year.
Many airlines have taken on the challenge of sustainability, including Air New Zealand, which introduced their FlyNeutral programme, making it possible for travellers to pay an optional fee to offset the carbon released from their travel.
But, according to statistics from late last year, only about four per cent of travellers were choosing to offset their carbon.
A return flight from Auckland to Sydney, for example, generates about 356kg of CO2 per economy-class passenger (534kg for business), and that can be offset by paying a fee of $9.04 - or $13.56 for business.
The airline provides a calculator to work out how much each journey will cost to offset, based on the current price of offsetting a ton of carbon.
Air New Zealand said in May last year that customers had purchased more than $1 million in carbon offsets while buying their flights, which went towards planting and preserving permanent forests which suck up carbon as they grow.
'TAKE A GOOD LOOK AT YOURSELF'
Professor Shaun Hendy, Director of Te Pūnaha Matatini, was a frequent flyer until recently, and told TVNZ's Breakfast programme that he decided not to fly for a full year because of the environmental impact.
"I am someone who flew a lot - I was a regular in the Koru Club - so it was about reflecting on my impact," Mr Hendy said.
Mr Hendy instead took trains between Auckland and Wellington, which he said provided "lovely views", but was also "very inconvenient".
"I've been making use much more of video-conferencing - connecting with people online, using online collaboration tools like Slack where you can keep in touch with teams around the country - and that's been really effective," he said.
"If you're one of the people that's living in the Koru Club, have a good look at yourself and see if you can cut down some of those flights."
Another frequent flyer, former rescue helicopter pilot Dave Greenberg, told 1 NEWS he had an environmental wake-up call from his god-daughter which made him consider his impact on the environment.
"I was brushing my teeth and she came in slammed her hand down on the faucet and said 'you're ruining my planet!' and that honestly was the first time I started thinking about it," he said.
"It is a dilemma," he said.
Mr Greenberg, who travels for work, estimated he had taken more than 90 flights in the past year.
"The flights that I book myself I tend to sometimes do the carbon offset, but most of my flights are paid for by my clients - they don't do anything like that," Mr Greenberg said.
He said he doesn't have a clear understand of where Air New Zealand's carbon offset fees actually go, and that it's a matter of "trusting Air New Zealand", which he does.
"As I understand it, the money goes towards planting trees or something."
SO HOW DOES 'OFFSETTING' WORK?
"The money collected goes towards buying carbon offsets from permanent native forestry and sustainable energy and biodiversity projects offshore," Air New Zealand's Head of sustainability Lisa Daniell says.
Over their lifetimes, plants suck up CO2 as they grow, because they're made, in part, from carbon.
People or businesses who own land with forests on it can apply to first have it certified, and then to receive money from the Emissions Trading Scheme (ETS) for not cutting down those forests, or for planting new forests and agreeing not to cut them down for a long time.
So, offsets basically pay for part of a forest to exist, and slowly soak up CO2.
For each ton of CO2 a forest removes from the air each year, the owner can sell one 'Carbon Credit' to the ETS.
There's an ETS marketplace controlled by the government, which governs the cost of those Carbon Credits.
Emitters buy Carbon Credits to offset their emissions, and once they do, the credits are removed from the market - so they can't be sold more than once.
AREN'T AIR NEW ZEALAND'S DOMESTIC FLIGHTS ALREADY CARBON NEUTRAL?
No - Air New Zealand pays the ETS for its emissions, but that doesn't offset emissions.
The airline has to report how much CO2 it emits to the government, and to purchase what are essentially permits to emit that CO2 through the ETS.
The government slowly reduces the availability of those permits, which drives up the price of emitting through scarcity, and that also incentivises climate-conscious business practices, because the more CO2 emitted, the more they have to pay into the ETS.
This is the government's main tool for meeting New Zealand's commitment to reducing emissions under the Paris Accord - by making emissions more expensive over time.
But those payments don't actually "offset" Air New Zealand's emissions by removing carbon from the air - that is done separately through their FlyNeutral programme when customers pay the additional fee.
SO MY OFFSET FEE IS SPENT ON TREES?
Yes, but Air New Zealand chooses to buy credits from native New Zealand forest plantings - not pine.
As well as native forest in New Zealand, the airline also funds certified overseas projects - like clean energy or green technology initiatives in developing countries.
The company says it doesn't take any fees to cover the operation of FlyNeutral, and that it's a 50/50 split between domestic and overseas projects .
But, currently, all of the airline's carbon offset projects in New Zealand involve growing and restoring native forests.
WHY NOT PINE TREES? THEY GROW FAST.
One of the best plants at sucking up carbon is the radiata pine because it grows so quickly.
That makes it a popular choice for other offsetting projects in New Zealand - but pine is also a problem, because it can reduce biodiversity, and can also be invasive.
Native bush plantation sucks up less carbon initially, but research suggests it ends up removing more carbon over time, Mr Hendy said.
"Over the long run natives win - over about 100 years a native forest will store more carbon, but if you're making a short term choice, if you want that carbon out of the air fast, then pine beats native," he said.
"If you look at the offsetting plantings that have taken place, they are very much dominated by pine, which of course has resale value."
AIR NEW ZEALAND: CARBON OFFSETS STILL THE BEST OPTION, RULES CHANGES WON'T AFFECT THEM
"We appreciate that carbon offsetting is a short-term solution and that real, measurable and gross emissions reductions must occur," Ms Daniell said.
"Nevertheless, until emission reduction technologies are available for aviation (i.e. sustainable aviation fuels and electric/hybrid aircraft) then offsetting (done well) remains the best option to mitigate the impact of flying.
"Sham projects are a real issue globally, which is why we have taken care selecting our projects and have an internal 'best practice' policy we adhere to."
The ETS's rules are changing soon, with the government's Permanent Forest Sink Initiative (PFSI) ending in 2021.
It was through this programme that many offset organisations registered and sold their credits, but it will be replaced by a more simplified system.
A spokesperson for Air New Zealand said "one of the reasons for this change is to make the category easier to understand/comply with to increase the number of permanent forests registered.
"It is not expected to materially impact the FlyNeutral programme.
"Air New Zealand will continue to only purchase units from permanent native forests for FlyNeutral."