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.

Putting your phone on airplane mode is required primarily to prevent electromagnetic interference with a plane's sensitive navigation and communication systems. While modern aircraft are heavily shielded, a concentrated amount of radio signals from hundreds of active cellular devices can still cause audible "interference noise" in the pilots' headsets, similar to the buzzing sound you might hear if a phone is placed near a speaker. More importantly, as a plane travels at high speeds and high altitudes, a phone not in airplane mode will continuously "ping" multiple cell towers on the ground at maximum power to maintain a signal. This can overwhelm ground-based networks by causing "signaling storms" as the device attempts hundreds of handoffs in a matter of minutes. In 2026, while many airlines offer controlled onboard Wi-Fi via specialized "picocells," airplane mode ensures your device doesn't bypass these systems to hunt for ground signals, which also preserves your battery life by stopping the energy-intensive search for elusive cellular towers at 35,000 feet.