The hangar roof says United Air Lines in both photos. The DC-3 is painted in United's scheme in this second photo, which was initially posted for a short while.
Now busily searching for likely places United would have had a hangar in the late '30s or early/mid '40s.
Edited to add: Perhaps the other plane in one of the pictures is from American Airlines.
Because of the hills, I nominate California, specifically Los Angeles, KLAX.
Last edited by seacue; 25th Oct 2009 at 10:02.