Air Force One and Japanese Air Force Two when operating on official business, and Cygnus One and Cygnus Two when operating outside of official business (e.g., on training flights). The aircraft always fly together on government missions, with one serving as the primary transport and the other serving as a backup with maintenance personnel on board. The aircraft are officially referred to as . Honours and emoluments Until the mid-1930s, the prime minister of Japan was normally granted a hereditary peerage (kazoku) prior to leaving office if he had not already been ennobled. Titles were usually bestowed in the ranks of count, viscount or baron, depending on the relative accomplishments and status of the prime minister. The two highest ranks, marquess and prince, were only bestowed upon highly distinguished statesmen, and were not granted to a prime minister after 1928. The last prime minister who was a peer was Baron Kijūrō Shidehara, who served as Prime Minister from October 1945 to May 1946. The peerage was abolished when the Constitution of Japan came into effect in May 1947. Certain eminent prime ministers have been awarded the Order of the Chrysanthemum, typically in the degree of Grand Cordon. The highest honour in the Japanese honours system, the Collar of the Order of the Chrysanthemum, has only been conferred upon select prime ministers and eminent statesmen; the last such award to a living prime minister was to Saionji Kinmochi in 1928. More often, the Order of the Chrysanthemum has been a posthumous distinction; both the Collar and Grand Cordon of the order were last awarded posthumously to former prime minister Shinzo Abe in July 2022. After relinquishing office, the prime minister is normally accorded the second or senior third rank in the court order of precedence, and is usually raised to the senior second rank posthumously. Certain distinguished prime ministers have been posthumously raised to the first rank; the last such award was to Eisaku Sato in 1975. Since the 1920s, following their tenure in office, Prime ministers have typically been conferred with the Grand Cordon of the Order of the Paulownia Flowers (until 2003 a special higher class of the Order of the Rising Sun), depending on tenure and eminence. However, honours may be withheld due to misconduct or refusal on the part of the prime minister (for example, Kiichi Miyazawa). See also List of prime ministers of Japan List of