There is no evidence to suggest that mobile use is a hazard on
aircraft. All of the evidence is circumstantial and anecdotal however
the airlines have taken the ultra safe approach of banning their use in
flight and limiting the use of other electronic devices.
Modern planes certainly have a lot more shielding from electronic devices,
whereas the older planes have limited shielding and are more susceptible
to electronic interference.
There are stories about navigation systems playing up and when a piece
of electronic equipment was turned off the "problem" resolved
itself but there is no absolute proof that the electronic equipment was
the cause. However as the airlines and the regulators have taken the approach
they have you need to ensure that your phone is off as the penalties are
The approach is certainly the correct one as the ramifications of equipment
on planes suffering from interference could potentially result in a disaster.
army office was recently sentenced to 70 lashes by a Saudi court for using
his mobile phone on a domestic flight, the court ruled that he put the
passengers at risk by using his phone during take and after the crew has
asked him to switch it off.