Biofuel usage for aviation was regarded as impractical in early days because most of them gets freeze at lower temperatures experienced at high altitudes. But there is a plant called Jatropha curcas which yields vegetable oil from it’s seeds and the oil obtained from this plant have its freezing point even lower than the freezing point of jet fuel. It is this property of jatropha oil which allows its usage in airplanes and aircrafts. Recently New Zealand Airlines powered one engine of Boeing 747-400 airplane by a 50-50 blend of jatropha oil and standard A1 jet fuel.
Since the production of jatropha is not on commercial scale therefore Air New Zealand couldn’t say anything about the cost of jatropha oil as compared to the standard jet fuel. Air New Zealand said that Jatropha biofuel could make airlines more environment friendly by reducing airplane emissions and also it could make airlines inexpensive too by reducing costs.