A change in the airmail rate of postage required the use of a 6-cent airmail stamp. The Post Office Department had on hand the remainder of the 5-cent airmail stamps of the 1928 issue, and the advisability of overprinting at least a portion of these was taken into consideration. No assurance existed that the new airmail rate would remain in effect for any great length of time, and the use of 5-cent stamps appeared possible at a later date. The 1928 stamps had not been used so rapidly as had been expected, since a new regulation permitted the public to use ordinary postage stamps on airmail. The Post Office Department supplied the British American Bank Note Company with the necessary number of panes of 100 subjects, as manufactured by the Canadian Bank Note Company, Limited, Ottawa. The surcharge, fully legible, did not obscure the postage stamp design, although it obliterated the original denomination numerals.
An allegory of flight, from a drawing by a staff artist of the Canadian Bank Note Company, Limited. Two winged figures, symbolic of flight, are poised against a globe representing the northern half of the western hemisphere, on which is indicated in shaded outline a map of Canada. The subject is classical and has been treated with a geographical background.