i used to attend the drive-in movies more often than the cinema. We often went with two or three cars full of people when teenagers.

I was sad when most around the country began closing ...usually for housing estates etc.

I remember starting to drive off a few times and forgetting to unhook the speakers from the window, also they weren't great if it started raining.

Fortunately, a number have reopened in recent years. Oh, and I found this interesting tidbit on Wikipedia:

"Drive-in theatres (also known as drive-in cinemas or just drive-ins) were once very popular in Australia. Although considered an American invention, there is evidence of outdoor cinemas in Western Australia where some patrons attended in their cars as far back as 1938, and it is possible that these facilities may even predate the first American-style drive-in theatre."