Oil usually used in lip balms has helped power a Virgin Atlantic jumbo jet into history as the first commercial airliner to be partly-run on biofuel - and Air New Zealand is tipped to follow within months.
But the Virgin flight from London to Amsterdam - powered by a biofuel made from babassu nuts and coconut oil - has been condemned as "high altitude greenwash" by Greenpeace.
The Boeing 747-400 had one unmodified engine running on a mixture of about 25 per cent biofuel and the rest standard jet kerosene.
"This pioneering flight will enable those of us who are serious about reducing our carbon emissions to go on developing the fuels of the future, fuels which will power our aircraft in the years ahead through sustainable next-generation oils, such as algae," Virgin boss Sir Richard Branson said.
Branson told reporters at Heathrow that Air New Zealand would stage its own test flight using algae in four months.
Air New Zealand said yesterday that a final decision on the fuel source and flight date was "probably a couple of months away". The airline is working with Boeing and Rolls Royce and aims to run an isolated engine of a 747 airborne from Auckland and has said it hoped to be off the ground by the end of the year.
Air New Zealand's research is concentrated on an oilseed crop, jatropha, a woody plant that can grow on barren, marginal land; and algae, high in oil content and able to grow on sewage ponds and in seawater.
Yesterday's Virgin flight, without passengers, is part of a joint project between the airline, Boeing and enginemaker General Electric. Airlines and aircraft makers are racing to develop a viable alternative to jet fuel as the price of oil rises and aviation is increasingly blamed for contributing to global warming.
"Two years ago, people said that was impossible. They said it would freeze at 30,000 feet," Branson said.
The test was "purely" to prove biofuel would work on commercial aircraft, he said.
Branson said he views algae-derived fuel as the most promising because it can be produced in large quantities without harming the environment. The fuel source used in the test flight wasn't plentiful enough to be a major resource for the airline industry he said.
"We've really got to move towards something sustainable," he said.
Greenpeace's chief scientist, Doug Parr, labelled the flight a "high-altitude greenwash" and said less air travel was the only answer.
"Instead of looking for a magic green bullet, Virgin should focus on the real solution to this problem and call for a halt to relentless airport expansion."
Babassu nuts are harvested from palms from the Amazonian rainforest and are used for lip balms and massage lotions.
"Biofuels are not a panacea, there are a whole load of issues," said John Strickland, director of London-based aviation specialist JLS Consulting. "Some have the issue of substituting food crops and they don't necessarily produce enough, in terms of volume, to replace kerosene."
Fuel accounts for 30 to 50 per cent of airlines' operating costs, and aviation contributes about 2 per cent of global carbon dioxide emissions, expected to rise to 3 per cent by 2050.
- additional reporting Bloomberg