Well, in practice, the reasons that U.S. airports are not privatized is first, that they can raise tax-exempt revenue bonds, where investors in bonds issued by private companies have to pay tax on the interest they earn.

那么，实际上，美国机场没有私有化的原因首先是，它们可以筹集免税收入债券，私人公司发行的债券的投资者必须为其赚取的利息纳税。