On November 22, 1935 Pan American Airways began carrying mail across the
Pacific Ocean from San Francisco to Manila, Philippines with its newly acquired
Martin M-130 flying boat. Pan American decided to expand this transpacific mail
service to passenger carrying service on October 21, 1936.
On April 21, 1937 Pan American Airways inaugurated new passenger/mail service
across the Pacific from San Francisco to Hong Kong with an intermediate stop in the
Portuguese colony of Macao. This opened commercial connections with Imperial Airways
and KLM for onward transit round-the-world. Several seized this opportunity to
post mail round-the-world.
It wasn't until May 20, 1939 when Pan Am inaugurated its transatlantic mail
"Southern Route" air service and until June 24, 1939 when Pan Am inaugurated its
transatlantic mail "Northern Route" air service that mail could transverse the globe
completely by regularly scheduled flights.
Who would be the first to send mail westward from the US round-the-world to be
flown back to the US on Pan Am's newly scheduled transatlantic flight service?
On June 20, 1939 Fidelity Stamp company sent an air mail multi-packet cover from
New York to Hong Kong to be forwarded round-the-world via Marseilles, France returning
to New York on July 11, 1939.
New York, NY Pan American Airways 06/20/39
Hong Kong Imperial Airways 06/29/39
Marseilles, France Pan American Airways 07/07/39
New York, NY 07/11/39