This Subpart applies to aircraft other than the following:
(a) balloons;
(b) airships;
(c) sailplanes;
(d) powered sailplanes;
(e) an aircraft for which any of the following is in force:
(i) a special certificate of airworthiness mentioned in regulation 21.186, 21.189 or 21.190;
(ii) an experimental certificate;
(iii) a special flight permit;
(iv) a provisional certificate of airworthiness.