For most acrylic paints, I don't recommend using rubbing alcohol as thinner since they contain serious solvents and other chemicals that damage the paint's consistency. Some brands of these paints, such as Vallejo Game Colors, are designed to be used with different types of solvents, so you can get away with using this kind while making sure not to use anything too strong, which may cause unwanted results. If you really want to try it out on airbrushing, then a good alternative would be isopropyl alcohol or even naphtha, commonly used in lacquer-based varnishes.