I'm not sure there are many drive-in owners here, so I thought I'd share a bit of our operation with y'all.
While many indoor operations run CDs of one kind or another, we've evolved (over 20 years) into a pretty nice system, run by a broadcast automation computer. The computer handles all our pre-show and intermission music, controls the projector automations and mixes the audio on our 3 screens and snackbar.
This service provides an announced program of music, snack-bar nudges and a personality that fits our place very well. To that, we add our own music, screen ad audio, drive-in commercials from 60's vintage Coca Cola reels, and actual Coke spots from the era, some in different languages. All in all, the system selects its program from over 4,000 available audio cuts.
For most theatres, this is exorbitant overkill... but for me, a former broadcast owner, announcer and engineer, it satiates that part of my professional past!
Anyhow, you're welcome to dial in and see what we do with our free time over here.