I can't see anything in FAR's part 91.21(a) that allows you such a dispensation when "travelling as SLF" unless the operator or pilot-in-command has specifically provided you with such a dispensation. Such devices are not covered under subsection (b) of that regulation.
Perhaps you could point out the regulation under your own countries rules that would permit a passenger to use an "air band" receiver in a commercial air transport where that device was not specifically permitted by the carrier?
The supposition that something is "certified to be used in flight" doesn't predetermine that you as a passenger are permitted to exercise that certification.
These regulations seem broadly similar to those found in other parts of the world, including the UK.
Perhaps you would be kind enough to remove your big cowboy hat, and point me to the regulation that you are relying on?