i dunt think your allowed ..cos i trieddd ..and they stopped me …and last time i went backk i tried again and nearlly worked .. but about 5 mins into me using ma lappy .. it went off .. came home wudnt turrn onn .. so went to get it checked it .. and the ppl who checked it said . that the hard drive was wiped clean and blown 
.. i had to return my lappy and take money back or replace .. nw i dunt have any lappy
as securityyy of avigation system and to avoid interferrance with onboard computers …am sure your not allowed to as far as i knww 
hwever, in my journeyy i make full use of my tiket spent …by killing foods and drinks .. land with a bellly full and walk around .. talking to ppl .. am very social in this matter .. awein strt talking to any one whose feeling bored ..as em first though k if they dunt mind unless they want to be bored … get to knw the crewww .. in this process few years backk .. the air hostess allowed me to even see the cockpit of a 747 PIA.. was in there for about 10 mins .. soo coool, i wna be a pilot cooll … even then after all this … maske use of the on board entertainment ..music/films..