(Conference report filed in House, H. Rept. 96-556) Maritime Appropriation Authorization Act for Fiscal Year 1980 - Authorizes appropriations for fiscal year 1980 for use by the Department of Commerce for: (1) acquisition, construction, or reconstruction of vessels, the construction-differential subsidy, and the cost of national defense features incident to the construction, reconstruction, or reconditioning of ships, except that (a) no funds so authorized may be used to subsidize the construction of any vessel which will not be offered for enrollment in a Sealift Readiness program approved by the Secretary of Defense, and (b) in paying the funds authorized, the construction subsidy rate otherwise applicable may be reduced by five percent unless the Secretary of Commerce determines that the vessel to be constructed is part of an existing or future vessel series; (2) payments of obligations incurred for the operating-differential subsidy, except that (a) no funds so authorized may be used for the operation of any vessel which is not offered for participation in a Sealift Readiness program and (b) under specified conditions, an operator receiving such funds may elect to suspend its operating differential subsidy with all attendant statutory and contractual restrictions for all or a portion of its ships; (3) research and development activities; (4) maritime education and training expenses; and (5) operating expenses including reserve fleet expenses. Authorizes additional appropriations for increases in salary, pay, retirement, or other employee benefits authorized by law, and for increased costs for public utilities, food service, and other expenses of the Merchant Marine Academy at Kings Point, New York. Permits the transfer between U.S. ports of merchandise with a foreign origin or destination by a vessel registered in the United States and owned by U.S. citizens when the merchandise is transferred to or from another vessel so owned and registered, provided that both such vessels are operated by the same carrier. Stipulates that such requirement shall apply only to vessels which that same operator owned, chartered or contracted for the construction of prior to the date of enactment. Amends the Merchant Marine Act of 1920 to provide that a State shall be considered a citizen in order to qualify as a first mortgagor for purposes of the Merchant Shipping Act.