You can not use your cell phone during a flight. This is prohibited by the FCC and applies to all commercial carriers of the world. The reason for this ban is safety as the frequency of cell phones can interfere with the instruments on the aircraft. However, you can use the on board cell phone that are provided by some carriers on the payment of a certain fee.
You may use a cell phone up until the time the plane's door closes, and then again after the plane touches down again. It is an urban myth that the cell phone's signal will affect the plane's controls, but in any case, even if you could use a cell phone while high up in the air, there would be no signal, since the phone would be too distant from any cell tower. In any case, think about 20, 30 years ago when they were no cell phones; we did fine not having a phone stuck to our ears 24/7. Besides what is the big rush?????
Gosh dear...it's a no-no! Flight instruments can be affected by your mobile phone frequencies and can cause error in the Pilot's reading. Please... Don't even think about it!
