5c green postal stationery envelope (H&G B12) with added pair 1935 10c deep green & single 5c red brown (SG 298/299) tied by straight line 'CORREO AEREO' cancellation addressed to APOLO with small 'CORREO AEREO' handstamp on front and '3 AGO 1936' datestamp on reverse. This was flown by the German pilot 'Hermann Schroth' in the trimotor plane 'Huanuni'. A very rare flight. (Photocopy of page from the Carlos Royuela airmail Exhibit accompanies illustrating two similar covers, unlisted by Muller).