Introduction to the Flight Mode

As a rule, the mobile phone has to be switched off before a flight takes off. This is because, the cell phone uses radio waves to communicate with its networking service. These waves might interfere with the radio waves that the aeroplane uses to communicate with the airport. This airplane-airport communication is very important for the safety of the plane. Thus, it is advised to switch off the mobile phone before embarking on a journey. 

But by doing this, we cannot use the other functions of the phone such as music playback, camera, writing documents, etc. This onstraint is solved by the flight mode.

The flight mode simply detaches the phone from its networking service (making you unable to make/receive calls & SMSes). Thus, the radio waves of the mobile phones are switched off too. Thus, the mobile phone simply becomes a digital toy, not interfering with the plane's radio waves in any way.

Windows Mobile - it does not have a separate flight mode. You can simply turn off the phone service from the Wireless Manager to turn off its waves. It works the same way as the Flight mode.Go to Settings --> Phone --> Flight mode --> On.