USA
USA, Stemplet helsag
1926. FIRST FLIGHT INAUGURATING CONTRACT AIR MAIL BOSTON - NEW YORK. BOSTON MASS. JULY 1, 1926. 4 X 2 CENTS.
USA, Stemplet helsag
1928. FIRST FLIGHT LA PORTE, IND. JULY 17, 1928. AIR MAIL CAM 27 BAY CITY - CHOCAGO.
USA, Stemplet helsag
1927. FIRST FLIGHT INAUGURATING CONTRACT AIR MAIL CLEVELAND - PITTSBURGH ROUTE PITTSBURGH PA. APRIL 21, 1927. 4 X 2 CENTS.
USA, Stemplet helsag
1926. FIRST FLIGHT INAUGURATING CONTRACT AIR MAIL BOSTON - NEW YORK ROUTE. BOSTON MASS. JULY 1, 1926. 4 X 2 CENTS.