Why are airplane passengers asked to put their phones in airplane mode? Per the FAA website's Safety Information page, “The FCC and FAA ban cell phones for airborne use because its signals could interfere with critical aircraft instruments. Devices must be used in airplane mode or with the cellular connection disabled.

People use airplane mode for several reasons beyond the legal requirement to prevent interference with aircraft navigation and pilot communication. In the air, it is mandatory because cellular devices attempting to "find" a signal at 30,000 feet can overload ground-based cell towers. On the ground, airplane mode is a popular "life hack" for saving battery life, as it stops the phone from constantly searching for Wi-Fi and cellular signals. It also allows for faster charging, as the device isn't using energy to maintain wireless radios. Many people also use it as a "Focus Mode" to temporarily block all incoming calls, texts, and distractions without turning the phone off completely. Additionally, travelers use it to avoid accidental roaming charges when crossing international borders, allowing them to use their phone as a camera or offline GPS without the risk of their carrier connecting to a foreign network and triggering expensive data fees.