Messerschmitt Me 163 Komet
"...the 163B was not a successful fighter. Several hundred 163Bs were built, but only 91 were operational as of December 31, 1944, and only 16 kills were attributed to 163s during the War. Note, however, that while under power or in a fast glide, the 163 could fly circles around any other fighter of its time."
Chief test pilot Rudy Opitz