Colombia, 1919, 2c carmine rose, "1er Servicio Postal Aereo 6-18-19" overprint, sound single, on flown cover from Barranquilla to Puerto Colombia, cds cancels dated "Jun 18 1919"; usual light cover creases as per correspondence, still Very Fine and attractive, very rare with only 160 covers flown; signed Sanabria and Bloch. Scott No. C1; $1,700 for faulty off cover  Estimate $2,000 - 3,000. $0 (Image)