Registered cover franked with 1930 'Death Centenary of Bolivar' issue set of four (SG 783/786) tied by commemorative 'Airplane' cancel dated DEC 17 1930 inscribed 'CENTENARIO DE LA MUERTE DE BOLIVAR' and by illustrated 'Airplane' cachet in black with boxed SAN SALVADOR registration marking and SAN SALVADOR cds dated the same day in purple alongside. Addressed to ECUADOR with PANAMA transit and GUAYAQUIL arrival marks on reverse. (Muller #20 rated 3500pts)