AirPlay and Bluetooth are two different technologies that enable a wireless audio experience with mobile devices, laptops and computers.
AirPlay is Apple's Wireless Platform that works over Wi-Fi to stream digital audio to AirPlay-enabled devices & speakers from Apple TV, iTunes, Mac, iPad, iPhone and iPod Touch. With its ability to support multi-room audio, you can stream music from iTunes to multiple speakers around your home. Airplay operates with low levels of audio compression so it can provide higher fidelity audio than Bluetooth. It can also stream audio over longer distances i.e. up to several hundred feet.
Bluetooth is a Universal Wireless Platform that enables compressed wireless audio streaming and speakerphone functionality to a single Bluetooth-enabled speaker system from smartphones, tablets, MP3 players and laptops (regardless of operating system). Bluetooth audio systems typically have a range of about 30ft.