Indirect air carrier
Indirect air carrier (IAC) means any person or entity within the United States not in possession of an FAA air carrier operating certificate, that undertakes to engage indirectly in air transportation of property, and uses for all or any part of such transportation the services of an air carrier. This does not include the United States Postal Service (USPS) or its representative while acting on the behalf of the USPS.
49 CFR § 1540.5
In addition to the terms in part 1500 of this chapter, the following terms are used in this subchapter: