Travelers are increasingly considering airlines’ sustainability efforts when they select a carrier, attendees at a conference on aviation’s environmental impact were warned.

“Public scrutiny over aviation carbon emissions is at an all-time high,” Aviation Environment Federation (AEF) director Tim Johnson said at the Greener by Design conference in London Nov. 7, staged by the Royal Aeronautical Society. “People will be asking not only ‘should I fly or not?’ but will be looking at carbon savings that can be made by individual airlines.” AEF is a UK-based organization campaigning for sustainable aviation.

The conference brought together specialists from a range of aviation-related sectors, including airline, the fuel industry and environmental technology researchers. The event also heard calls for governments to modify current carbon taxes to more actively encourage decarbonising measures, and suggestions that long-haul flights should make refueling stops to improve efficiency.

A groundswell of public concern over climate change has become apparent over the past two years, particularly in Europe. This sentiment has crystallized into movements such as the “flight shame” phenomenon in Sweden, where travelers are being actively discouraged from flying.

Five European governments already have passenger charges intended as “green” taxes, and five more are looking at imposing them. There have been consistent complaints from the airline industry that the taxes are not effective in reducing emissions but are instead used by governments for general fund-raising. The UK has the world’s highest such tax in the form of the airline passenger duty (APD), effectively a departure tax.

Despite complaints from airlines and passengers, the reality is that governments had become accustomed to this revenue stream and are unlikely to give it up, London Heathrow Airport director of sustainability Matt Gorman said.

Energy Transitions Commission chairman Adair Turner suggested finance ministers could use aviation taxes in more imaginative ways, especially as governments mandating increasing levels of sustainable aviation fuels (SAFs) become a likely prospect.

A minister “could say ‘I’m going to increase APD, but I’m going to increase it by 50% for non-SAFs but reduce it by 50% for SAFs,’” he said. “That would change it from being just a tax to a carbon-related tax.”

That, in turn, could give airlines that make greater efforts to increase the use of SAFs an opportunity to lower fares, giving them a competitive edge.

There are also operational measures airlines can take to reduce fuel burn, Cranfield University emeritus professor of aerospace engineering Ian Poll said. With gas turbine engines having an optimum range of around 4,500 km, long-haul flights could make refueling stops at that point, he said. This would probably be unpopular with airlines and passengers, he said, but would save 5%-10% in fuel burn.

The increasing move toward ultra-long-haul routes is an inefficient use of fuel, he said, but an even worse, and much larger, problem is the use of long-haul aircraft on relatively short-haul routes.

The offsetting of carbon emissions by passengers is regarded as a bridging measure until new technologies can be integrated into aircraft fleets. However, even this holds dangers, Poll said.

He described carbon offsetting as “the biggest-ever opportunity for organized crime.” Criminals would not have to take the risk of hauling suitcases of drugs; they could simply sell airline passengers nonexistent carbon offsets.

Alan Dron,