There can be some diffs between Car, Plane, and Heli fuel. While the methanol and nitro remain the same (except percentages), the oil is different. I don't just mean differnet % or castor vs synthetic. Differerent oil weights and additive packages are used based on application. In gerneral, for most beginner engines, this is nothing to really worry about. I.E., the average plane engine will burn heli & car fuel just fine. However, some specilized engines, or engines subjected to very high heat (cars/helis), fair better with differnet oil blends (i.e., weight and additive package.) This is why the different fuels.