El Salvador 1930 First Flight Airmail Cover to Mexico
Just 1572 letters were sent on the first flight, many affixed with one or two stamps from the first airmail issue. This cover to Mexico has examples of each of the five stamps from the first printing (Scott C1 to C5) with an additional 10c orange without overprint. Note that the 40c on 50c has 'raised i and o in Servicio' variety. First day cachets plus forwarding agent's oval handstamp and two Servicio Aereo Mexico receiving handstamps to reverse.