We will examine the cost of meeting biofuel consumption goals for US commercial aviation using renewable fuel produced using a Hydroprocessed Esters and Fatty Acids (HEFA) process from renewable oils. If soybean oil is used as a feedstock, meeting the aviation biofuel goal in 2020 will require an implicit subsidy to biofuel producers of $2.69 per gallon of renewable jet fuel, but this cost is reduced significantly if oilseed crops can be grown in rotation with existing crops. We will also highlight important interactions between the goal for renewable jet fuel and mandates for ground transportation fuels in the US.