Worldwide Stamps and Postal History

1927 Registered cover from Manyoni, Tanganyika to Ontario marked "via New York - Detroit Airport" with KUT 15c and 40c tied by Manyoni c.d.s and an uncancelled USA 10c air mail stamp; and 1930 cover from G.B to California marked "Air mail NY - Los Angeles" with G.B 11⁄2d and US 5c air mail stamp both tied by Didsbury, Manchester machine. US Air mail stamps could be used on mail from abroad going to the USA to pay for internal US air mail, and were sold in certain foreign countries for this purpose. (2).
Suggested price: £ 120-150