As a passenger, can I use my handheld radio in commercial flights?
I don't know if you are "authorized" to... but I can tell you that it likely won't work.  

I've tried a handheld aviation radio in a commercial cabin, and was unable to hear the ATC side of transmissions at all.  This was likely due to having a very short antenna inside a large metal cylinder, a long way from the source of the transmission.

It was nearly impossible to follow the communications when I could only hear my flight crew's side of the conversation.