Justifiable and Efficient Transportation Substitutes Act or the JETS Act This bill prohibits the use of federal funds for the travel expenses of any cabinet official on: (1) a non-commercial, private, chartered flight; or (2) any plane owned, operated, rented or leased by the government. The prohibition must continue until the President prescribes guidelines to be published in the Federal Register describing prohibited and permissible travel by a cabinet official. With regard to permissible travel under the guidelines: scheduling requirements may not be cited except in the case of travel to or from a region covered by a declaration of an emergency or a major disaster, or for reasons of national security; the unavailability of commercially-available flights may be cited if it is accompanied by a written finding by the President or the Chief of Staff to the President issued on a case-by-case basis; and no comprehensive waiver may be allowed for a cabinet official. After the date of publication of the guidelines, any travel by a cabinet official otherwise prohibited must be disclosed to the General Services Administration (GSA). GSA must publish information on the disclosed travel on its public website.