For the biofuels industry, aviation fuel markets could provide an outlet for biofuels producers that might be attractive relative to current markets. Today, the single largest domestic biofuel is ethanol, which is blended into motor gasoline for cars and trucks. However, ground transportation biofuel markets face declining gasoline sales, limits on ethanol blending in gasoline, market risks for higher ethanol blends and hydrocarbon fuels, and competition from non-liquid fuels (natural gas, battery-electric, or fuel-cell hydrogen-powered vehicles). Aviation fuel markets are likely less vulnerable to competition from non-liquid fuels (U.S. Department of Agriculture et al. 2012) because the benefits of greater energy density of liquid fuels are substantial in aviation due to the energy efficiency implications of hauling the fuel itself and the physical constraints of airplane design and performance. Another feature of aviation fuel markets that is relevant to biofuels producers is the concentration of jet fuel demand at major airport hubs (U.S. Department of Agriculture et al. 2012). This concentration could simplify supply chain control and logistics, potentially facilitating biofuels supply to these locations, although possibly also raising concerns about market power of the fuel purchasers. The challenges to biofuels entering aviation fuel markets are numerous and significant and include business and financial risks of delivering a specialized, highly regulated fuel at a competitive price to a financially volatile industry. Neither these potential benefits nor the challenges are assessed in detail in this report. The CAAFI provides guidance about the development of this business, including airline requirements for fuels purchases and discussion of business risks (Miller and Heimlich 2013).