No State or political subdivision thereof may adopt or attempt to enforce any standard respecting emissions of any air pollutant from any aircraft or engine thereof unless such standard is identical to a standard applicable to such aircraft under this part.

(July 14, 1955, ch. 360, title II, § 233, as added Pub. L. 91–604, § 11(a)(1), Dec. 31, 1970, 84 Stat. 1704.)