I fly frequently on a few different US airlines, all with the same basic announcement: - All electronic devices must be powered completely off during the first

I fly frequently on a few different US airlines, all with the same basic announcement: - All electronic devices must be powered completely off during the first and last 10 minutes of flight. - Laptops and phones can be on during the rest of the flight if all radios are off (including WiFi and Bluetooth). - The growing exception to the above is on planes with WiFi, where you can turn WiFi on during cruise. No other kinds of radios are allowed, even receive-only radios.