I'd be very grateful for any help in identifying this U.S. plane. Other photos in the album look like they're from WW2.
What you have there is I believe a Boeing Model 80A-1:
You can read more about it on Wikipedia: Boeing Model 80
The Model 80 air transport aircraft was built in the mid 1920's. It is notable as being the aircraft used for the first flight to feature a flight attendant, which were registered nurses at the time.