Delta SkyMiles American Express card members can earn double SkyMiles when paying 2003 federal income taxes with the Delta SkyMiles card. Members paying individual federal taxes with plastic can earn double miles when paying any balance due on their taxes (Form 1040); requesting an extension of time to file a federal income tax return (Form 4868); or paying their estimated federal taxes (Form 1040-ES). In addition, members can earn one mile for every eligible dollar spent when paying their state income taxes on the card. This offer is available with classic, Options, Gold and Platinum Delta SkyMiles credit cards only.