Air New Zealand, which has saved more than $500 million since 2005 through an energy-efficiency drive, was rewarded for its efforts at an event in Auckland last night.
The national carrier took out the supreme award at the Energy Efficiency and Conservation Authority (EECA) Awards.
The authority, set up to promote energy efficiency, said the airline was avoiding 142,000 tonnes of CO2 emissions each year, a figure that dwarfed all the other award entries combined.
It said Air New Zealand had cut its fuel use by 15 per cent through measures such as culling unneeded weight on board its aircraft, getting its pilots to taxi on one engine instead of two and introducing aerodynamic "winglets" on its Boeing 767s.
The authority said that when the carrier received its Boeing Dreamliner aircraft in 2014 it would have the world's youngest and most fuel-efficient commercial fleet.
EECA chief executive Mike Underhill said Air New Zealand's achievement brought positive spin-offs for all New Zealanders.
"Air New Zealand is a highly visible ambassador for our whole economy," he said.
Other companies receiving awards included ASB in the large business category, Golden Bay Cement for renewable energy and New Zealand Post in the public sector and energy management categories.