The New York Times has reported that "United Parcel Service Inc. aims to cut its airline fleet's greenhouse gas emissions 42 percent from 1990 levels during the next decade by using less fossil fuel in its jets. UPS currently operates the world's ninth-largest private airline fleet, with 228 jumbo jets in service and 314 more chartered aircraft. The Atlanta-based company said in a sustainability report today that it plans to invest in more fuel-efficient aircraft models, introduce biofuels, reduce runway idling and optimize flight routes, among other things, to slash its fuel costs and emissions of carbon dioxide and other heat-trapping gases."