DC-4 and DC-6 are two of my favorite large aircraft in history. So graceful and beautiful, yet practical and utilitarian.
Had the honor of seeing Redbull's beautiful DC-6 in person at the 2012 Bodø Air Show.
Notable other airliners I particularly like from that era are the Lockheed Constellation and the world's first modern long range airliner, which looks remarkably like a DC-4, here in the colors of the Danish Airlines:
Sadly, no Fw-200 exists today. During the war the Fw-200 took on a much more sinister role of course, but during the happy '30s in Europe it was the dream ride of the flying public.