Tennessee Code Title 67. Taxes and Licenses § 67-6-349

(b)(1) If a dealer pays to the department the tax imposed by this chapter on fuel or petroleum products sold to an air common carrier, and if the fuel or petroleum products are subsequently used by the air common carrier in a manner that renders the product exempt from tax under subsection (a), then the dealer may take a credit equal to the amount of tax previously paid to the department, if all of the following conditions are satisfied:

(2) The dealer must maintain documentation that is sufficient to establish entitlement to the credit, and the documentation must be maintained for a period of three (3) years from December 31 of the year in which the credit is taken on the return. Nothing in this subsection (b) shall be construed as preventing the dealer from filing a claim for refund pursuant to § 67-1-1802 in lieu of taking a credit on the tax return; provided, however, that in no case shall the same tax be subject to a refund and a credit.