During takeoff and landing, passengers are typically asked to turn off all electronic devices or switch them to airplane mode for several reasons:

1. Potential Interference with Aircraft Systems: Although the risk of interference with aircraft navigation and communication systems by personal electronic devices (PEDs) has been debated and studies have shown mixed results, airlines and regulatory authorities prefer to err on the side of caution. Older aircraft systems were thought to be more susceptible to electromagnetic interference. However, newer aircraft models are designed to be resilient against PED emissions.
2. Safety Protocols: Before takeoff and immediately before landing are critical phases of flight. During these periods, passengers are required to stow loose items and be prepared for any potential emergency situations. Having electronic devices turned off ensures that passengers are not distracted and can focus on safety instructions.
3. Clear Communication Channels: Pilots rely on clear communication with air traffic control, especially during takeoff and landing. Turning off devices or switching to airplane mode minimizes the chance of any noise interference with the cockpit radio equipment.
4. Adherence to Regulations: Airlines follow guidelines from aviation regulatory bodies such as the Federal Aviation Administration (FAA) in the United States and the European Aviation Safety Agency (EASA). These agencies provide guidance on the use of PEDs during flights.

In recent years, with advancements in technology and updated regulations, many airlines allow the use of PEDs in airplane mode throughout the entire flight, including during takeoff and landing. However, passengers should always follow the specific instructions given by the airline crew, as policies can vary between airlines and countries.