I recently went on a trip with several friends and we rented a new Ford Expedition. The integrated audio system in the car supported multiple Bluetooth devices with a history (including previous renters) but as far as I could tell not more than once device at a time. Every time we started the car we had to select Sources -> Bluetooth -> Connect -> ${device name} -> Sources -> Bluetooth -> ${device name}. It was a huge hassle and a 3.5mm cable would have been far easier and sounded better.

So one interesting aspect of the airpods is seemingly automatic pairing, without having to dive in settings, through what seems like near-field communication. I'm curious to see if they've solved the multi-device pairing problem too.