A similar flying boat design called the Martin 156 and named Russian Clipper, was built for the Soviet Union; it had a larger wing (giving it greater range) and twin vertical stabilizers.

[1] All three were eventually lost; the first in 1938 disappeared on a flight over the Pacific, then in 1943 one flew into a California mountainside in poor weather, and finally in 1945 the last broke up on landing in Trinidad and Tobago.

One helped evacuate about 40 civilians from the ill-fated Wake island at the start of WW2, which was soon invaded by the Empire of Japan.

[4] Their range and capacity made them valuable for trans-ocean military flights during World War II.

[7] In January 1945, the China Clipper left Miami on Pan Am's first scheduled flight to what is now Kinshasa in the Democratic Republic of the Congo.

It broke up and sank during landing at Port of Spain, in the West Indies islands of the British colonies of Trinidad and Tobago on January 8, killing 23 of those on board.