Not sure of the year, but the photo was likely between 1950 and 1952 at Midway Airport in Chicago. Back in the days when flying was an adventure.
This family appears to be admiring a Chicago & Southern Air Lines DC-4. C&S got its start in 1935 flying airmail, and eventually merged with Delta Air Lines in 1953. The company called itself Delta-C&S for two years. The merger allowed Delta to operate on international C&S routes and fly one of their first international jet flights with Convair 880 service to Jamaica and Venezuela.
H/T to WilliamsSW for pointing out that C&S operated from Midway, not O’Hare as originally posted.