On December 17, 1935 the Douglas Sleeper Transport (DST), made its first
flight with pilot Carl Cover at the controls and Frank Collbohm as co-pilot.
The aircraft lifted off from Clover field, Santa Monica and was airborne for
an hour and a half. The flight was described as "very routine,"" so routine
in fact, that no Douglas executives took the time to watch it and no
photographs of the event were taken. Further test flights followed and apart
from the addition of a small dorsal fin to the tail to improve directional
stability, no major problems arose.
An Approved Type Certificate, ATC No. 607, was issued on 21 May 1936 and the
DC-3 was born.