If you get some miles on a credit card for airlines (for example), you do not need to address this on your tax return.
IRS looked at taxing these miles when employees got them some years ago, however it became an accounting nightmare, as some were personal, some were business, and then it is difficult to determine the value and many miles expire, never used.
So just disregard the fact that you may have earned some miles, when making a payment via a credit card.
