That quoted price was the spot price. It doesn't include Federal or other taxes.
Let's suppose that it did include taxes. Federal tax for jet fuel for non-commercial-aviation use is 21.9¢/gal so even if the quoted price of $3.135/gal included federal tax, the without-tax price would still be $2.916/gal, which is a lot closer to $3/gal than $2/gal.
(Gas for commercial aviation use is also subject to the federal transportation tax and harder for me to figure out.)
