The primary reason for the "airplane mode" or "off" requirement is to prevent electromagnetic interference with the aircraft's sensitive navigation and communication systems. During takeoff and landing—the most critical phases of flight—pilots rely heavily on clear radio signals to communicate with Air Traffic Control and receive precise altitude readings. While modern 2026 aircraft are heavily shielded, a concentrated burst of signals from hundreds of un-synced mobile devices can potentially create "noise" in the pilot's headsets or cause minor fluctuations in cockpit instruments. A secondary but equally important reason is passenger safety and attentiveness. In the event of an emergency evacuation, flight attendants need passengers to be fully alert and able to hear verbal commands without the distraction of headphones or being hit by a heavy laptop that could become a projectile during a sudden stop.