Lighter, more fuel efficient planes were the buzzwords at the Paris Air Show this week, where the world's top jetmakers showed off their efforts to reduce pollution and cut fuel costs.

The Airbus A380 superjumbo parked on the runway at the show in Le Bourget even spelled it out in big blue letters across its side: "Greener, Cleaner."

Also at the show was Eurocopter's "Bluecopter," a new helicopter that is being developed to keep carbon dioxide emissions to a minimum.

"There is a huge amount of pressure on the industry to take action on climate change, on reducing (fuel) consumption," said Paul Steele, head of the Air Transport Action Group, an association for environmental standards.

European aircraft maker Airbus and its rival Boeing have both said they aim to reduce fuel consumption of their airliners by a quarter by 2020. The efficiency drive has financial goals as well as environmental ones.

"Fuel consumption has always been one of the main criteria" for airliners, said Christian Dumas, deputy head of Airbus in charge of environmental issues.

Dumas boasted that the new A380 "consumes less than three litres per 100 kilometres per passenger" and that the A350 "will be a bit better."

In a bid to reduce fuel consumption and carbon dioxide emissions, aircraft makers are testing various biofuels and trying to make the planes as light as possible using composite materials such as hi-tech plastics and carbon fibre.

New planes like the Airbus A350 and the Boeing 787 are built with a composite material content of as high as 50 percent.

A four-seater plane being exhibited by French small aircraft maker Issoire Aviation at the Paris Air Show was entirely made of composite materials and weighs in at just 500 kilogrammes (1,340 pounds) when empty.

The efficiency drive has expanded to the air transport system as a whole, with airlines trying to manage routes better in order to cut flight time and save fuel -- raising fears among some experts of possible safety issues.

Boeing has carried out tests in San Francisco for making approach and landing in a straight line instead of in steps as is the current practice.

This would allow a saving of 40-percent of fuel during landing, said Billy Glover, head of environmental strategy at Boeing.

There have been attempts to reduce the length of time the engines are operating including tests by Airbus that would mean engines are only switched on when the plane is actually on the runway.

"The airlines are really making effort to take weight off the aircraft," Steele said.

In the quest for lighter planes, every little bit can help.

US carrier Northwest Airlines has reportedly stopped including spoons with its in-flight meals unless absolutely necessary and Japan Airlines has shortened its blankets by a centimetre (half an inch).