Boeing 737:
The 737 is the oldest aircraft type still in service with Koutei Koku, predating the 747s by a year, with 58 airframes owned by the airline at various times. Consisting of ten 737-200, eight 737-300 and forty 737-800s.
Six 737-200s were delivered in 1969-71 to serve domestic routes to small and unimproved airports that needed a bit more capacity than the NAMC YS-11. For the second time in a few years, the airline choose a Boeing product over the Douglas DC-9. This time no favourable deals or earlier avaliability was involved, Koutei just Choose the 737s longer range and higher payload. A second batch of two planes was delivered in 1975, with another two following a few years later, so that by 1979 there were ten in service. During their service there were no serious occurrences. One airframe was retired in 1992, another four in 1997-98 and the last five between 2001 and 2002.
Between 1988 and 1990 eight 737-300 were delivered to replace the older 727-200s on domestic routes. Reliable like the other 737s they remained in the fleet until 2009, when six were retired while newer 737-800s entered service. Two airframes were retained for charter flights and ultimately withdrawn in 2013.
Last 737 type to join the fleet, the 737-800 was ordered in 2005 with a remarkable 40-aircraft deal with Boeing. Recieved between 2007 and 2016, they expand medium-range thin routes both on the domestic and international market wherever capacity is too small for the A330, 777 or 747 and they also replace some of the older A320 in the fleet. They serve business-oriented domestic routes as well as flights to Sapporo and Narita, Guam, Honolulu and even Anchorage with an all business class configuration. They are slated to serve well into the 2020s but things might change if, as rumored, Koutei Koku does end up ordering Airbus A321-NeoLR in 2018. In this eventuality other rumors says the -800s might be exploited to form a low-cost subsidiary. Nothing is official yet.