Air Post Stamps. 1928, Airplane over the Globe, imperforated plate proof of 5c in dark olive brown, printed on india paper, block of four, no gum as issued, NH, VF, Unitrade #C1P, C.v. C$800 as singles (Image)

Air Post Stamps. 1931, Airmail Pictorial issue, complete set of three imperforated plate proofs in black, printed on thick unwatermarked (15k) or watermarked paper, no gum as produced, VF and rare (Image)