Currently the only method for enabling Apple CarPlay's mirroring functionality on a car's entertainment system is via a physical USB cable connection. A similar limitation also exists for smartphone users on the other side of the fence, with Android Auto presently only available via a physical connection.
That need for a wired connection is reportedly set to be lifted when iOS 8.3 is released, though. TechCrunch has obtained a screenshot of the CarPlay wireless setup screen via a beta tester, who has access to a pre-release version of iOS 8.3.
It's not clear what wireless protocol CarPlay will utilise, although the two most likely candidates are Bluetooth and Wi-Fi. It's also unknown how long an iPhone can last whilst connected to a vehicle's audio system via wireless CarPlay.
Wireless CarPlay is still at least a few months away, as the latest version of iOS available to the general public is 8.1.3; at present iOS 8.2 is in its fifth beta iteration.
For current owners of CarPlay-compatible headunits, an update to the audio system's firmware may also be required to enjoy wireless CarPlay.
Check out our review of Pioneer's audio systems with CarPlay functionality, as well as our hands-on with the Parrot RNB6 unit that supports both Apple CarPlay and Android Auto.