This is essentially a B-29 Superfortress 3.0 – the Boeing 377 Stratocruiser (the C-97 Stratofreighter was 2.0), here flying out of San Francisco. Pan Am was the first to take this plane on a commercial flight (San Francisco to Honolulu) in 1949. Boeing built 55 for commercial use. All of them were retired by 1963.
The back is interesting. I have a couple of cards from the Chicago area, dated in the early 50s, sent to “Lucky Mail Bag” or “Good Luck” to this address (a residence). The last name of the addressee is “Leja” . I have no idea what the “WCPCC” means.
My dad and mom lived in Chicago in the ’30s. They were young and, from what I heard them tell when I was a kid, they had a fine old time.