Airplane mode is the setting in smart devices. When it is turned on, it does not receive or transmit wireless signals. It also disables Bluetooth, wi-fi and mobile data. Airplane mode helps to save battery life of phone.
What is the need to toggle Airplane mode during flight ?
During flight, your phone gets out of reach of connection towers of Earth. Then it sends strong electrical signals to find nearby towers. These strong electrical signals interfere with other gadget installed in airplane like navigation system and pilots headphone. Due to which navigator does not work properly and does not fetch accurate data and deviate the pilot from actual path. An annoying noise signals are created in pilots headphones, which cause inconvenience and disturbance for him.
In some countries like USA, criminal charges are charged against the people who does not turn on airplane mode during flight.
During flight, people are advised to switch of their phones or turn on airplane mode before take off.