Aviation companies are facing increased scrutiny about their role in causing climate change.
As the polluters of the sky, the industry is responsible for 859 million tonnes of Co2 per year. That's 2 percent of global greenhouse gases.
It's led to a backlash by people worried about the environmental damage caused by their flights, with a growing "no-fly" movement.
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This week, aviation leaders met in South Korea where they expressed grave concerns about the impact this scrutiny could have on their profits.
One answer could be using biofuels. However their increasing costs are part of the reason the aviation industry has recently lost billions of dollars.
Air New Zealand's boss Chris Luxon says biofuels are too expensive right now. Instead, he's looking at flights powered by batteries.
"We really have a fundamental challenge because there isn't enough technology or innovation to be able to fly aircraft with the energy that we need to without using fossil fuels at this point in time," he says.
"Within seven to 10 years, we should be able to think we could have an electric or a hybrid-electric turbo-prop aircraft flying within New Zealand."
But that will only work regionally as the technology doesn't reach the distances to get overseas.
Aviation leaders know they need to prove that a sustainable future is in their reach - or face increasing push-back.