; and (II) less the amount calculated under subclause (I)(bb) for the fourth preceding year; and (ii) may be used only for the aviation investment programs listed in subsection (b)(1). . (b) Enforcement of guarantees Section 48114(c)(2) is amended by striking 2017 and inserting 2021 . 1006. Extension of expiring authorities (a) Marshall Islands, Micronesia, and Palau Section 47115(j) is amended by striking 2017 and inserting 2021 . (b) Extension of compatible land use planning and projects by State and local governments Section 47141(f) is amended by striking September 30, 2017 and inserting September 30, 2021 . (c) Extension of pilot program for redevelopment of airport properties Section 822(k) of the FAA Modernization and Reform Act of 2012 ( 49 U.S.C. 47141 note) is amended by striking September 30, 2017 and inserting September 30, 2021 . B Airport improvement program modifications 1201. Small airport regulation relief Section 47114(c)(1) is amended by striking subparagraph (F) and inserting the following: (F) Special rule for fiscal years 2017 through 2021 Notwithstanding subparagraph (A) and subject to subparagraph (G), the Secretary shall apportion to a sponsor of an airport under that subparagraph for each of fiscal years 2017 through 2021 an amount based on the number of passenger boardings at the airport during calendar year 2012 if the airport— (i) had 10,000 or more passenger boardings during calendar year 2012; (ii) had fewer than 10,000 passenger boardings during the calendar year used to calculate the apportionment for fiscal year 2017, 2018, 2019, 2020, or 2021, as applicable, under subparagraph (A)