This chapter provides some data on a few other types of military aircraft which have been the subject of preliminary design studies to determine their potential using hydrogen as fuel. It discusses several methods of manufacturing liquid hydrogen. The use of liquid hydrogen as fuel for advanced design aircraft represents an opportunity to begin a transition to a militarily secure and economically acceptable energy supply system. Use of hydrogen as fuel has been shown to provide significant benefit in performance to many types of aircraft. The pilotless aircraft is fueled with liquid hydrogen. A category of aircraft which showed especially great performance improvement by using LH2 rather than conventional jet fuel was aircraft designed for high altitude, long endurance applications. Another class of military aircraft which has been analyzed to determine its potential for using LH2 fuel is the land-based Antisubmarine Warfare category.