; and (2) the results of the review conducted under subsection (b). 745. Electromagnetic spectrum research and development The Administrator shall develop a program to research the use of spectrum in the civil aviation domain, including aircraft and unmanned aircraft systems. This research shall, at a minimum, address— (1) how, operating within an Unmanned Aircraft System Traffic Management system, unmanned aircraft systems can safely use, for control link, tracking, diagnostics, payload communication, collaborative-collision avoidance (e.g. vehicle-to-vehicle communications), and other purposes— (A) aviation-protected spectrum; (B) commercial communications networks, such as mobile communications networks; and (C) any other licensed or unlicensed spectrum; (2) how the reallocation of spectrum assigned for use within frequency bands adjacent to those allocated for position, navigation, and timing may impact the safety of civil aviation; and (3) measures to protect and mitigate against spectrum interference in frequency bands used by the civil aviation community to ensure public safety. VIII Aviation Revenue Provisions 801. Expenditure authority from Airport and Airway Trust Fund (a) In general Section 9502(d)(1) of the Internal Revenue Code of 1986 is amended— (1) in the matter preceding subparagraph (A) by striking October 1, 2018 and inserting October 1, 2023 ; and (2) in subparagraph (A) by striking the semicolon at the end and inserting or the FAA Reauthorization Act of 2018