I have taken another look at the pic and I think that this may be the C-87 transport version, of the B-24. Note the windows along the shoulder of the fuselage and no turrets. The C-87 would have had the legs to make a flight to Lisbon, Portugal IIRC.
The American Flag was there to let the Germans, for instance, know that this was an "AMERICAN" aircraft and hence was neutral. (he he) After Pearl Harbor Hitler declared war on the United States whiuch of course did away with any pretense of neutrality.
I will have to do some research on this and I will try to have an answer for you tomorrow.
Regards
alfa6 ;>}
That's what I was wondering....thanks ever so much Alfa.
Please also note the red circle in the star on the insignia (the first photo). The circle was removed after Pearl Harbor to avoid any confusion with the Japanese Red Rising Sun or "Meatball" insignia.