After 1945 rising car ownership and suburban and rural population led to a boom in drive-in theaters, with hundreds being opened each year. More couples were reunited and having children, resulting in the Baby Boom, and more cars were being purchased following the end of wartime fuel rationing. By 1951, the number of drive-in movie theaters in the United States had increased from its 1947 total of 155 to 4,151.
That, as they say, was then. This, as they say, is now: