Auto Mechanic VS Aircraft Mechanic

Did you know that an auto mechanic is paid better than an aircraft mechanic? My husband recently told me this interesting little bit of information. He believes that it has to do with demand, there is a much higher demand for auto mechanics than there is for aircraft mechanics. I think that this is pretty strange, especially when you consider what an aircraft mechanics job entails. Did you know that? Do you think that this is fair? Why do you think they get paid more? Do you think my husband is right about the demand for one being higher than the demand for the other?