Panama, 1929, 10c red registration envelope on cream, 154x93mm, used with two 1c Balboa (197) singles and Airmail 1929, 10c orange inverted overprint (C2a) and 1930, 15c on 10c orange (C3), all tied by three strikes of purple "Agencia Postal, Panama, May 23" duplexes, First Flight cover to Ecuador (AAMC F9-5b), purple "R/Agencia Postal de Panama/Primer Servicio de Correo Aereo/Panama-Ecuador" framed registry handstamp, Guayaquil (5.29) and Quito (5.30) backstamps, Extremely Fine and attractive. Higgins and Gage No. C3. Estimate  $150 - 200. Only a handful of the covers on this flight received the commemorative registry cachet. $0 (Image)