This beautiful original Kodachrome taken in January 1943, shows a Glenn L. Martin Company PBM-3R Mariner flying boat picking up dual Navy and Pan American Airways markings, likely at the manufacturer’s factory in Baltimore.
National Archives and Records Administration 80-G-K-1142
Pan Am operated a fleet of unarmed Navy-owned PBMs on regular NATS-organized transport runs between San Francisco and Pearl Harbor in the last three years of WWII. The airline had experience with big Martin seaplanes already, operating Martin Model 130s as “China Clippers” before (and later during) the war.
Martin PBM-3R “Mariner” transport aircraft. Caption: Scene in a Nats PBM-3R’s cockpit, during a flight to Jamaica, August 1943. Photographed by Lieutenant Junior Grade Wayne Miller, USNR. Catalog #: 80-G-377237
Some 31 PBM-3s were converted to the above “PBM-3R” transport configuration while 18 new-build PBM-3Rs were constructed as well.
As detailed by Airvectors:
These machines had armor and armament removed, with the turrets faired over; a reinforced floor, cargo doors, and a hoist; and removable seating for 20 passengers, though it was nothing unusual for them to carry 33 or more.
Deliveries began in the fall of 1942. Most PBM-3Rs served with the Naval Air Transport Service (NATS), where they were often flown by commercial pilots in Navy uniform.