Implementation of the use of hydrogen as fuel for aircraft can be brought about either as a result of development of the technology by the military, or as a cooperative international venture, in which case it would enter general use by way of commercial airlines. The first step toward development of an operational capability with liquid hydrogen as fuel for aircraft is development of the technologies involved in its use. Development of facilities incorporating advanced technologies for production and liquefaction of hydrogen at each of the major air terminals to be used by the liquid hydrogen (LH2)-fueled aircraft was to be an integral part of the program. Despite the many advantages offered by use of LH2, many segments of the commercial aviation industry are not now enthusiastic about hydrogen-fueled aircraft because they foresee enormous difficulties in making a transition between the present petroleum-base fuel system to a hydrogen system.