Top right corner mint example with INVERTED AIRPLANE error, hinged in selvedge leaving the elusive airmail VF NH, very scarce thus. (Unitrade CL43a) (Image)

Cat. Value 3000 $

A similar lot, VF LH (Image)

Cat. Value 2000 $

Series "20" mint IMPERFORATE pane of eight additionally showing the elusive "Grounded Plane" variety; small marginal ink notation at lower right, a striking sheet, VF NH (Unitrade CL43b + c; catalogued as four normal pairs) (Image)

Cat. Value 3900 $

A similar lot, small marginal ink notation at lower right. (Image)

Cat. Value 3900 $

Series "20" mint IMPERFORATE pane of eight, VF NH (Unitrade CL43c; catalogue value as four pairs) (Image)

Cat. Value 3900 $

A similar lot (Image)

Cat. Value 3900 $

A similar lot (Image)

Cat. Value 3900 $

A similar lot (Image)

Cat. Value 3900 $

A similar lot (Image)

Cat. Value 3900 $

A similar lot (Image)

Cat. Value 3900 $

A similar lot (Image)

Cat. Value 3900 $

A similar lot, small marginal ink notation at lower right (Image)

Cat. Value 3900 $

A similar lot, but a block of four (Cat. as two pairs) (Image)

Cat. Value 1950 $

Series "12" mint IMPERFORATE pane of eight with "high" airplane variety - positioned higher than normally encountered; small marginal ink notation at lower right, VF NH (Unitrade CL43c; cat. as normal pairs) (Image)

Cat. Value 3900 $