Canada CLP31919 (August 25) $1 Red and Blue Aero Club of Canada, an unusual postmarked airmail stamp the first we recall seeing with what we can describe as a mute double oval intaglio cancellation in black; accompanying Greene Foundation certificate states: CLP3, used, genuine, however not used on the 1919 Aero Club flight nor on the 1920 Grand Army of Canada flight; cancelled at some time with an unknown O; manuscript GAC Carnival written on stamp. A rare item