{"data":{"id":"us/14-cfr-221.53","jurisdiction":"us","citation":"14 CFR 221.53","heading":"Proportional fares.","body":"(a) Definite application. Add-on fares shall be specifically designated as “add-on” fares on each page where they appear.\n(b) A tariff may provide that fares from (or to) particular points shall be determined by the addition of add-ons to, or the deduction of add-ons from, fares therein which apply from (or to) a base point. Provisions for the addition or deduction of such add-ons shall be shown either directly in connection with the fare applying to or from the base point or in a separate provision which shall specifically name the base point. The tariff shall clearly and definitely state the manner in which such add-ons shall be applied.\n(c) Restrictions upon beyond points or connecting carriers. If an add-on fare is intended for use only on traffic originating at and/or destined to particular beyond points or is to apply only in connection with particular connecting carriers, such application shall be clearly and explicitly stated directly in connection with such add-on fare.","path":["Title 14—Aeronautics and Space","CHAPTER II—OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS)","SUBCHAPTER A—ECONOMIC REGULATIONS","PART 221—TARIFFS","Subpart F—Requirements Applicable to All Statements of Fares and Charges"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-14.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:24:20Z","sha256":"f02425a28fdeb2bff3e79d730b54718bee8b1651173065799f6d314fc4d2b280","source_id":"us-cfr","stale":true,"prev":"us/14-cfr-221.52","next":"us/14-cfr-221.54"},"notice":"GroundRules: Original legal text. Not legal advice."}