Not sure where you are, but in the UK it is not possible for a member of the public to obtain authority to use a scanning receiver, or any type of receiver covering frequencies other than those employed for general broadcast (BBC) or amateur radio. (I think you can monitor Navtex, but I'm not certain). Of course you need a licence to receive TV transmissions too!
Particular parts of the frequency spectrum are authorised for use by certain individuals in the course of their work, E.g. Police officers may use their radio channels, pilots and controllers may use frequencies in the air band, etc. However, the "authority" only permits those individuals to use radio communication directly connected with their work. This means that police officers, ambulance drivers or airline pilots cannot go home and listen in to the frequencies they use at work.
That's the law in the UK.