The XF-701 Sigrdrífa Fighter/Interceptor was a class of fighter used by XCOM before the creation of the Firestorm and the F-302X Grim Reaper. It is the spiritual successor of the XB-70 Valkyrie Bomber. The Interceptor utilizes twin pulse detonation engines that allow it to exceed and sustain velocities in excess of Mach 3.2. It has an armament of six AIM-54X Avalanche nuclear missiles that allows it to outrange Sectoid plasma beams in combat. Production was stopped after the development of the Firestorm.