b'359292C 30 Sept.1921 (AAMC.55) Adelaide - Alice Springs cover to Unley, SA carried by Francis Birtles and pilotLt FS Briggs in a DH4 on their Railway Commission survey flight, franked with KGV 2d orange tied Adelaide 27OCT21 roller cancel on arrival also tieing Northern Territory Stamp Duty 1d violet with manuscript date 20/10/21 affixed alongside on face, plus 1939 letter from Birtles authenticating cover as most likely sent from Alice Springs or Charlotte Waters; one of only three items known; Cat $3500. (2 items).Ex Frommer, sold for $2700 in the September 2016 sale of his Grand Prix Pioneer Australian Air Mails Collection $2,6003,0009393C 4 Dec.1921 Perth - Derby (AAMC.56a) Jas A Dimmett Motor Accessories Castrol Oil advertising cover carried by Western Australian Airways on the inaugural flight of Australias first regular airmail service; with 3d Kangaroo (surface fault) and KGV 2d orange tied PERTH cancels, paying domestic letter rate plus 3d airmail surcharge, black PERTH DERBY/4DE21/AERIAL MAIL skeleton cachet on face, DERBY/20DEC21/WESTN AUSTRALIA arrival datestamp on reverse, Cat. $1100. The service was suspended soon after leaving Geraldton on 5 Dec due to the fatal crash of one of the three aircraft; the mail was flown back to Perth and sent on by the steamer SS Bambra. .$600800'