; sponsor The terms public-use airport and sponsor have the meanings given such terms in section 47102 of title 49, United States Code. 789. Updating presumed to conform limits Not later than 24 months after the date of enactment of this Act, the Administrator shall take such actions as are necessary to update the FAA’s list of actions that are presumed to conform to a State implementation plan pursuant to section 93.153(f) of title 40, Code of Federal Regulations, to include projects relating to the construction of aircraft hangars. 790. Recommendations on reducing rotorcraft noise in District of Columbia (a) Study The Comptroller General shall conduct a study on reducing rotorcraft noise in the District of Columbia. (b) Contents In carrying out the study under subsection (a), the Comptroller General shall consider— (1) the extent to which military operators consider operating over unpopulated areas outside of the District of Columbia for training missions; (2) the extent to which vehicles or aircraft other than conventional rotorcraft (such as unmanned aircraft) could be used for emergency and law enforcement response; and (3) the extent to which relevant operators and entities have assessed and addressed, as appropriate, the noise impacts of various factors of operating rotorcraft, including, at a minimum— (A) altitude; (B) the number of flights; (C) flight paths; (D) time of day of flights; (E) types of aircraft; (F) operating procedures; and (G) pilot training. (c) Report Not later than 1 year after the date of enactment of this Act, the Comptroller General shall brief the appropriate committees of Congress on preliminary observations, with a report to follow at a date agreed upon at the time of the briefing, containing— (1) the contents of the study conducted under subsection (a)