I saw Star Wars in the back seat of a '72 Olds Delta 88. Back then everybody would arrive at the drive-in hours before the movie started...(in order to get a good parking spot). Once we found a good spot, Mom would let us disappear to the drive-in's playground...all the kids would play in the playground area until it got dark enough for the trailers to start, then the moms would start shouting for their kids to come back to their cars....
I saw Star Wars many times after that but only once in the drive-in. I know I didn't get the full effect of the picture and sound that others got when they saw it in a in-house theater but to me it was just as fun and awe inspiring....
As a 9 year old boy in the 70's who's biggest thrills came from collecting baseball cards and on the weekends running my COX model dragster up and down my parents driveway, Star Wars was mind blowing....before Star Wars, movies in the 70's were all about crime, drugs, racial tension, war or anti-war.....we didn't go to the drive-in often, so Star Wars was radical because it was so different than what movies were about then....Star Wars was fun.
Anyway that's my two cents, hope it helps....