14 CFR § 93.219 - Allocation of slots for essential air service operations and applicable limitations.
Whenever the Office of the Secretary of Transportation determines that slots are needed for operations to or from a High Density Traffic Airport under the Department of Transportation's Essential Air Service (EAS) Program, those slots shall be provided to the designated air carrier or commuter operator subject to the following limitations:
(a) Slots obtained under this section may not be bought, sold, leased or otherwise transferred, except that such slots may be traded for other slots on a one-for-one basis at the same airport.
(b) Any slot obtained under this section must be returned to the FAA if it will not be used for EAS purposes for more than a 2-week period. A slot returned under this paragraph may be reallocated to the operator which returned it upon request to the FAA office specified in § 93.221(a)(1) if that slot has not been reallocated to an operator to provide substitute essential air service.
(c) Slots shall be allocated for EAS purposes in a time period within 90 minutes of the time period requested.
(d) The Department will not honor requests for slots for EAS purposes to a point if the requesting carrier has previously traded away or sold slots it had used or obtained for use in providing essential air service to that point.
(e) Slots obtained under Civil Aeronautics Board Order No. 84-11-40 shall be considered to have been obtained under this section.