From the National Geographic Tumblr Found:
Cars parked at a drive-in theater with a 53-foot wide screen in Alexandria, Virginia, December 1941.
Photography by J. Baylor Roberts, National Geographic
While our friends at National Geographic don’t speculate, I wonder if the film above is Rise and Shine, released by Twentieth Century Fox on November 21, 1941. IMDb offers this synopsis:
Stupid football player is kidnapped by gangsters. Lunatics abound: former footballer now dancer, professor interested in magic, gangster who makes horse noises when excited.
Among others it featured Milton Berle and Walter Brennan.