Indiana Code Title 6. Taxation § 6-6-13-8

Sec. 8. A person who makes a purchase in a transaction that is exempt from the aviation fuel excise tax under section 7 of this chapter may issue an exemption certificate to the retailer instead of paying the tax.  The person shall issue the certificate on forms and in the manner prescribed by the department.  A retailer accepting a proper exemption certificate under this section has no duty to collect or remit the aviation fuel excise tax on that purchase.