“Over time, it’s going to cost us all more, but it’s the right approach that we must take,” Delta Air Lines chief executive Ed Bastian told the BBC.
Aviation is responsible for about 2.5% of the carbon emissions that are warming the planet, according to the International Energy Agency.
Critics argue the best way to reduce them is by flying less.
Atlanta-based Delta says that after spending $30m (£22.4m) a year on carbon-offsetting it has been carbon neutral since March 2020.
It has also pledged to spend $1bn over the next decade to cancel out all the emissions it creates.
More fuel-efficient planes, sustainable aviation fuels and removing carbon from the atmosphere are some of the ways it hopes to achieve this.
Reducing carbon emissions is crucial if the world is to limit global warming to 1.5C above pre-industrial levels as agreed in Paris in 2015, and has been the focus of the COP26 climate change summit in Glasgow.
Andreas Schafer, professor of energy and transport at University College London, says it will “cost trillions rather than billions of dollars” to move the global aviation sector to net zero carbon emissions.
Preliminary results from his team’s research suggest airfares would need to increase by 10%-20% to cover the costs.
“In the short-term, government support will be needed with those costs as decarbonising aviation will be extremely challenging, and current efforts will need to be scaled up dramatically”, says Prof Schafer.
Mr Bastian concedes it is an ambitious goal that his airline won’t be able to achieve alone.
“It’s the biggest long-term challenge this industry faces,” he said. “We’re in an industry that’s classified as hard to decarbonise because we don’t have the bio-fuels or the sustainable aviation fuels (SAFs) en masse yet that we’re going to need.”
Delta aims to be using 10% sustainable aviation fuel by the end of 2030.
Many airlines and fuel companies are investing in SAFs. Other technologies being developed involve turning food waste into jet fuel and using carbon dioxide pulled out of the air.
However, these still cost more than traditional jet fuels and the quantities needed are also seen as problematic.
According to the US government, global demand for jet fuel is set to more than double by 2050 .
The number of passenger flights is set to jump from a pre-pandemic 4.5 billion to 10 billion by 2050, according to the International Air Transport Association (IATA).
IATA director general Willie Walsh told the BBC that while creating the levels of SAF production needed was a big challenge, “it is perfectly possible if industry and governments work together”.
“Production increases will bring the cost down to competitive levels. We’ve seen similar increases in the development of solar and wind power in recent decades.”
At the UN climate change summit in Glasgow, 23 countries have pledged to work together to get the aviation industry to net zero carbon emissions by 2050. More efficient energy use, sustainable aviation fuels and electric aeroplanes are all part of their ambitions.
However, environmental campaign group Greenpeace says the agreement is “brazen greenwashing”.
“This announcement is full of scams like offsetting, and excessive optimism on so-called ‘sustainable aviation fuels’ and future aircraft designs,” says Greenpeace’s Klara Maria Schenk.
“But it lacks the one thing that’s needed to deliver the goal of limiting temperature rise to 1.5C which is tangible action to prioritise green travel and reduce flights.”
Whilst many businesses and individuals have used the pandemic as a chance to re-evaluate their carbon footprints, Mr Bastian thinks the number of flights will return to pre-pandemic levels.
“All forms of travel are on the way back. Families are the part of the travelling public that we’re most happy to see, because there’s been some really difficult stories over time of families not being able to connect for long [periods]”.
Business travel is also returning because video meetings can’t replace everything, says Mr Bastian.
“There’s a real unity and sense of purpose that we have when people get back together in person”.
That desire to travel helped Delta to report a $194m profit in the three months to the end of September, its first profit since the pandemic began.
Before the pandemic Delta was the world’s second biggest airline, flying 200 million passengers in 2019. As of September it was operating at 71% of its pre-pandemic capacity.
The recovery in its domestic US market has been fastest, with long-haul routes to Asia the slowest. That echoes the pattern seen in a recent forecast from planemaker Boeing, which forecast a full recovery of global aviation would take until 2024.
Like other airlines, Delta has received billions in government support to get through the pandemic, but is hopeful of a brighter future now the US has reopened its borders to international travellers.
Mr Bastian says this may take some adjusting to and there may be long queues at airports as Covid vaccines and paperwork are checked.
However, he is confident in the airline’s outlook and says the pandemic was “an opportunity to invest in our future”.
Now the airline is making money again he says: “We hope to be able to maintain that and go into the new year as a profitable carrier.”