1919 2c carmine rose, "1" with serifs variety (position 5), used on first flight cover from Barranquilla to Puerto Colombia, signed Herbert Bloch, cover creases away from the stamp, which is well centered and v.f. Only 20 copies of this variety were printed (catalogue value for used off cover) cat. $4250 (Cat No. C1a) (Image)

Cat. $4250, Est.$3,000

1920 10c Flier in Plane Watching Biplane, faint violet cancel (looks unused), v.f., signed Kessler, cat. $1875 (Cat No. C5) (Image)

Cat. $1875, Est.$800

1920 10c Fuselage and Tail of Biplane, canceled on piece by clear oval Cartagena CCNA cancel, fresh and v.f., signed Bloch, Roumet, etc. Only 17 used examples of this stamp have been recorded, cat. $3800 (Cat No. C7) (Image)

Cat. $3800, Est.$1,500

1920 10c Plane at Red, unused without gum as issued, fresh and v.f., signed Kessler, etc. Only 41 unused examples have been recorded, cat. $3500 (Cat No. C9) (Image)

Cat. $3500, Est.$1,500

1920 10c Ocean Liner, used in combination with 3c National stamp on small cover from Cartagena (22 February 1920) to Barranquilla, v.f., with arrival pmk on back, accompanied by 1966 BPA certificate (catalogued as used off cover) cat. $2750 (Cat No. C10) (Image)

Cat. $2750, Est.$1,500