“Mobile phone signals can interfere with aircraft navigational and landing guidance systems.” The relationship between phone signals and navigational systems is not an exact science, which is why everyone we spoke to was careful in their language.

The "ban" on using mobile phones to make calls during a flight is rooted in both technical safety concerns and social considerations. Historically, the Federal Communications Commission (FCC) banned the use of cellular phones in the air because a phone moving at 500 mph at a high altitude can "see" hundreds of cell towers at once, potentially overwhelming and disrupting the cellular network on the ground by rapidly jumping between "cells." From a safety perspective, the Federal Aviation Administration (FAA) and airlines are extremely conservative; they worry that the radio frequency (RF) emissions from older or uncertified devices could interfere with the sensitive avionics and navigation systems in the cockpit, especially during critical phases like takeoff and landing. While modern planes are shielded against such interference and many airlines now offer in-flight Wi-Fi, the ban on voice calls remains largely for social reasons. Surveys consistently show that a majority of passengers and flight attendants are strongly opposed to allowing voice calls, as the noise of dozens of people talking in a cramped, enclosed cabin would create a significant "nuisance" and potential for "air rage." Thus, "Airplane Mode" allows you to use the device's offline features safely while keeping the cabin quiet and the ground networks stable.