49 U.S.C. § 41719

1. (a)An air carrier may not terminate interstate air transportation from a nonhub airport included on the Secretary of Transportation’s latest published list of such airports, unless such air carrier has given the Secretary at least 45 days’ notice before such termination.
2. (b)The requirements of subsection (a) shall not apply when—
   1. (1)the carrier involved is experiencing a sudden or unforeseen financial emergency, including natural weather related emergencies, equipment-related emergencies, and strikes;
   2. (2)the termination of transportation is made for seasonal purposes only;
   3. (3)the carrier involved has operated at the affected nonhub airport for 180 days or less;
   4. (4)the carrier involved provides other transportation by jet from another airport serving the same community as the affected nonhub airport; or
   5. (5)the carrier involved makes alternative arrangements, such as a change of aircraft size, or other types of arrangements with a part 121 or part 135 air carrier, that continues uninterrupted service from the affected nonhub airport.
3. (c)Before January 1, 1995, the Secretary shall establish terms and conditions under which regional/commuter carriers can be excluded from the termination notice requirement.
4. (d)In this section, the following definitions apply:
   1. (1)The term “part 121 air carrier” means an air carrier to which part 121 of title 14, Code of Federal Regulations, applies.
   2. (2)The term “part 135 air carrier” means an air carrier to which part 135 of title 14, Code of Federal Regulations, applies.
   3. (3)The term “regional/commuter carrier” means—
      1. (A)a part 135 air carrier; or
      2. (B)a part 121 air carrier that provides air transportation exclusively with aircraft having a seating capacity of no more than 70 passengers.
   4. (4)The term “termination” means the cessation of all service at an airport by an air carrier.