Airplane mode is a function that shuts off mobile data, Wi-Fi, and Bluetooth features when activated. You can turn on Wi-Fi and Bluetooth once Airplane mode is on, but you are unable to use cellular data that may interfere with certain radio frequencies. Turning off just cell data allows you to use a Wi-Fi connection instead of data. Turning both off has been shown to conserve battery life as both shut down services and features on your phone. However, Airplane mode may be the better choice for conserving battery.