I tried formatting the flash drive using ExFat on my MacBook Pro, but my car would not read/could not see the flash drive. Formatting the flash drive from a windows computer solved the problem. Since formatting on a Mac worked for you, it seems there may have been something else causing an issue on my end that reformatting via windows resolved.
Driving around Tampa today with CarPlay was fun. However, I almost became one of those distracted driver statistics that CarPlay was designed to prevent (too much fun trying out all the new functions).