Which aircraft is depicted on 1941 U.S. Post Office airmail stamps?
It appears to be only an artist's conception and is an amalgam of several different designs, but apparently largely based on the Douglas DC-3 aircraft, the Lockheed Electra, and the Beech 18.



The livery bears a striking resemblance to American Airline's DC-3 sleeper service, which operated during that era.



http://usstampgallery.com/view.php?id=1021c6191539bc1ca404bccf78595b7fdc0f06fd