1. Why is there a restriction on using mobile
phones in Airplanes?
This is as a matter of abundant precaution, to avoid any
possible interference of avionics electronic equipment &
navigation systems. In the much older generations of
avionics & navigation equipment of 30 years ago, there
was a small probability that at very short range of a few
inches, that the signal of an analog phone could interfere
with the planes electronic systems. This is almost
impossible with modern digital mobile phones and
modern avionics equipment, which have inbuilt
mechanisms to reject unwanted signals. Nowadays this is
more a matter of maintaining discipline on board. In fact,
you can always use the handsets in Flight Mode. Also,
many airlines want you to use their expensive on-board
communications systems for which they can bill you
heavily.