Gulfstream X-54
... that despite being designated as an X-plane by NASA, the Gulfstream X-54 project does not otherwise involve the space agency?
... that despite being designated as an <a href="./List_of_X-planes" id="mwC8o" rel="mw:WikiLink" title="List of X-planes">X-plane</a> by <a href="./NASA" id="mwC8s" rel="mw:WikiLink" title="NASA">NASA</a>, the <b id="mwC8w"><a href="./Gulfstream_X-54" id="mwC80" rel="mw:WikiLink" title="Gulfstream X-54">Gulfstream X-54</a></b> project does not otherwise involve the space agency?