49 U.S.C. § 41701
Classification of air carriers
The Secretary of Transportation may establish—
(1)
reasonable classifications for air carriers when required because of the nature of the transportation provided by them; and
(2)
reasonable requirements for each class when the Secretary decides those requirements are necessary in the public interest.
( Pub. L. 103–272, § 1(e) , July 5, 1994 , 108 Stat. 1140 .)