29In subsection (4) of section 18 of the said Act of 1968 (interpretation), for the words from "' relevant" onwards there shall be substituted the words " ' enactment' has the same meaning as in the [1949 c. 67.] Civil Aviation Act 1949 and 'relevant overseas territory' has the same meaning as in section 30(1) of the [1980 c. 60.] Civil Aviation Act 1980. "