Big tin can. I remember going out to Tracy CA in the late 60's with my dad to see their retired -6B's. There was some story about taking the engines off and trucking them back to SFO for the next flight.
But it was a sea of red, white and blue tails.
The DC-4 was one that got away from me, as far as I can remember. I've had rides in Aloha's DC-3 (paratrooper seats), other DC-3"s. more United DC-6B flights that I can count, DC-7s, Viscounts and Convair 440's (I think that was the model). All of their jets until 787.
It's forgotten that airlines ran a lot of milk runs back when.
I had a grandmother down in Southern California. We'd fly San Francisco to Monterey. When dad didn't have seniority we'd get bumped by soldiers from Fort Ord, but usually went on through to Salinas, King City, Lompoc and Santa Barbara in the 440.
They'd fly low over San Simeon so the passengers could look at Hearst Castle.
I don't think the DC-4 did airlines much good, not being pressurized.
Santa Fe Railroad had an attractive Santa Fe Skyway DC-4 to haul freight around the route.