Section 23.01 - Basis and purpose(a) This subpart establishes instructions for the display of distinctive markings of Coast Guard vessels and aircraft, including Coast Guard ensign and commission pennant and Coast Guard emblem.(b) Coast Guard vessels and aircraft are distinguished from other vessels and aircraft by an ensign; a personal flag, command pennant, or commissioned pennant, if so authorized; or other identifying insignia or marking.CGFR 57-35, 22 FR 6765, Aug. 22, 1957, as amended by CGFR 66-67, 31 FR 15239, Dec. 6, 1966