The aviation industry is being unfairly targeted over climate change and future reductions in aircraft emissions should be based on technological innovation rather than regulation, Airbus chief Tom Enders said Wednesday.

"We think it's a little bit unfair that the aviation sector is singled out for attack by many environmental groups, maybe because we are more visible than other groups," Enders told a media briefing in Auckland.

Environmental activists are pressing for lower emissions from the aviation industry and are urging travellers to cut back their air travel.

Last week in Bangkok signatories to the 1997 UN Kyoto Protocol promised to explore ways of curbing the harmful gases that planes emit into the atmosphere.

But the Airbus chief executive said placing curbs on air travel and emissions would be the wrong solution.

"We are absolutely convinced that the solution is not new taxes, new constraints, but technology and innovation," he said.

Technical innovation has already made large commercial aircraft about 70 percent more efficient that they were 30 years ago and new technology, such as bio-fuels, would lead to further improvements.

"Roughly 30 percent of all jet fuel by 2030 could be coming from bio-fuel," Enders said.

This would come through a second generation of biofuels, which unlike some current bio-fuels, would not displace food crops, he said.

Steep rises in global food prices have been partly blamed on crops and land being diverted for use in bio-fuels.

Airbus, which shares a global duopoly with Boeing in the production of large commercial aircraft, in February tested a synthetic fuel made from natural gas, which is cleaner and more efficient than the kerosene currently used.

It also recently tested a fuel cell used to power some electric and hydraulic systems in one of its aircraft.

"At Airbus we are spending a couple of hundred million euros a year in technologies related to environmental friendliness. That's a lot," Enders said.

Airbus chief operating officer for customers, John Leahy, told the briefing that new generation Airbus aircraft, such as the A380 superjumbo and the A350 airliner currently in development had made huge strides in fuel efficiency.

In 1985 eight litres (2.1 US gallons) of fuel was needed to fly each passenger 100 kilometres and now the industry average is five litres, he said.

In 20 years, the industry average will be three litres, a level the A380 achieves now.

At the Bangkok talks Norway and the European Union led calls to include air and sea travel into Kyoto and any subsequent pact agreed in 2009.

The Bangkok talks aimed to set a schedule for a treaty by the end of next year covering emissions cuts when Kyoto's obligations run out in 2012.

Although aircraft are becoming more fuel-efficient, the rapid growth of the industry means overall aviation emissions are rising rapidly.

Leahy said the aviation market was set to continue doubling in size every 15 years.