Alternative gasoline, diesel fuel, marine diesel fuel, jet fuel, and flexible fuel compositions are disclosed. The compositions include an alcohol and/or a glycerol ether or mixture of glycerol ethers, which can be derived from renewable resources. When combined with gasoline/ethanol blends, the glycerol ethers can reduce the vapor pressure of the ethanol and increasing the fuel economy. When added to diesel fuel/alcohol blends, glycerol ethers improve the cetane value of the blends. All or part of the diesel fuel in the compositions described herein can be biodiesel fuel and/or synthetic fuel derived from a Fischer-Tropsch synthesis process. Fischer-Tropsch synthesis can also use feedstocks derived from sources other than crude oil, such as methane, methanol, ethanol, lignin and glycerol, which can further reduce reliance on foreign sources of crude oil. When used in jet fuel, glycerol ethers can replace all or part of conventional deicing additives, thus lowering skin toxicity, and glycerol ethers ability to reduce particulate emissions can lower the appearance of contrails. When used in marine diesel, the reduction in particulate emissions can be environmentally significant. In another embodiment, the alternative compositions comprise gasoline, ethanol, and n-butanol, and in one aspect, the ethanol and/or n-butanol can be derived from renewable resources. Fuel additive compositions, including glycerol ethers and hydrocarbons and/or alcohols, are also disclosed.