05/22/2005. Remarks by Nico Braas: "The same German-Spanish team that also designed the HA-100, designed later a light-weight supersonic interceptor with delta shaped wings designated as HA-300. For aerodynamic testing, a manned glider version was built by Hispano as the HA.P-300. However, the first flight was aborted soon after lift off behind a CASA HE-111 towing plane because the plane showed to be highly unstable. No further attempts were made to fly it further. The HA-300 was eventually developed and built by the Egyptian Helwan works."