The Junkers F 13 was the world’s first all-metal transport aircraft,
developed in Germany at the end of World War I.
It was an advanced cantilever-wing monoplane,
with enclosed accommodation for four passengers.
322 planes of the type were manufactured,
an exceptionally large number for a commercial airliner of the era,
and were operated all over the globe.
It was in production for thirteen years
and in commercial service for more than thirty.

The F 13 was a very advanced aircraft when built,
an aerodynamically clean all-metal low-wing cantilever
(without external bracing) monoplane.
Even later in the 1920s,
it and other Junkers types were unusual
as unbraced monoplanes in a biplane age,
with only Fokker’s designs of comparable modernity.
It was the world’s first all-metal passenger aircraft
and Junkers’ first commercial aircraft.

The designation letter F stood for Flugzeug, aircraft;
it was the first Junkers aeroplane to use this system.
Earlier Junkers notation labelled it J 13.
Russian-built aircraft used the designation Ju 13.
(SOURCE: WIKIPEDIA)