Following a two-hour flight in an Air New Zealand Boeing 747 last month, airline officials are excited about the prospects for the latest in biofuel. The so-called "second generation" of biofuels used in the test was refined and blended in the United States by Honeywell subsidiary UOP. Air New Zealand's test aircraft flew with a 50-50 mix of regular jet fuel and the biofuel feeding one of its Rolls-Royce turbofans, which will be torn down and examined for any ill effects. Part of the tests included shutting down and restarting the engine. The new biofuel uses oil derived from seeds of jatropha trees rather than corn or other crops. Earlier biofuels were criticized because producing them would tax the Earth's capacity to produce food. In contrast, the jatropha tree grows wild in Central America, has spread on its own to South America and Asia, and could be cultivated in most areas of the globe. India already uses jatropha-based fuel in trucks and buses and has planted trees alongside railways to supply the need. Reportedly, jatropha-based fuels emit similar levels of carbon compared with fossil fuels, but proponents argue that growing the trees offsets a substantial portion of the carbon footprint. Air New Zealand hopes that by 2013, up to a tenth of its fuel needs will be met with jatropha-based fuel.