Farming and biofuels organizations are hopeful that ethanol could be used to power passenger jets, but making that dream a reality hasn’t been easy. That's partly because even as many farmers would benefit from a huge new market for corn, turning ethanol into jet fuel relies on federal tax credits that could require capturing carbon dioxide at refineries and moving the gas hundreds of miles through pipelines across the Midwest. Opponents have gone before regulatory authorities in several states to oppose the lines, and frequently they have succeeded in at least slowing the process. A key decision is expected soon in Iowa. Several companies have proposed pipelines but some dropped their plans in the face of opposition and delay.