Panama to US late 1930-1940's two Airmail Covers to Boston  C42 and C7

Airmail envelope from C.O. Mason in  Panama City to Allied Kid Company, Boston, bearing 1937 20c red Jose Gabriel Duque (1849-1918) from the 1937 Fire Brigade commemorative,SC C42 tied by clear PANAMA duplex dated MAR 8, 4 PM. No year.  The second also from C,O. Mason to Allied Kid in Boston bearing 1930 green  Aeroplane over map of Panama Scott C7 with Nov 15 duplex cancel

A fine example of Panama–U.S.