Google has made it possible for car owners who have Android Auto to connect wirelessly to a mobile phone. Incidentally, that only works on a select number of Google smartphones for the time being.
According to the support page, users must have a Pixel smartphone, or a Nexus 5X or 6P. Older Google smartphones are not supported, and in addition, the Android Auto app must be updated to version 3.1. The receiver built into the car must also be suitable for wireless connections.