((a)) ** .—** Amounts equal to the amounts authorized under sections 48101–48105 of this title remain in the Airport and Airway Trust Fund established under section 9502 of the Internal Revenue Code of 1986 () until appropriated for the purposes of sections 48101–48105.

((b)) ** .—**

((1)) Amounts in the Fund may be appropriated only to carry out a program or activity referred to in this chapter.

((2)) Amounts in the Fund may be appropriated for administrative expenses of the Department of Transportation or a component of the Department only to the extent authorized by .

((c)) ** .—** In a fiscal year beginning after , the Secretary of Transportation may obligate or expend an amount appropriated out of the Fund under only if a law expressly amends section 48104.