I sloped down to a local antique store this afternoon and, by digging a little bit, came across this tidy gem:
No publisher is noted, but it has to be a puff piece for Delta, comfortably dated to between 1949 and 1951. Delta took delivery of their first DC-6 in 1948. They were retired in the early sixties as jets took over. Why 1951? Because, as pointed out on other posts on the web, postage rates for postcards went up to 2 cents in ’51. This was printed prior to that.