While I have no experience in the matter, it would appear that the FCC in the USA requires pilots operating aircraft flying outside of the USA to have a “Restricted Radiotelephone Operators Permit”, the application form for which is FCC 605, and which may be found here. Applicants enter their personal details and, in the section “Basic Qualifications”, state that they have not been convicted of a felony (criminal offense) by any state or federal court. Then they pay a fee of around $70 - that’s it.
I’m assuming that other licensing authorities require a similar permit or certification. If so, and assuming also that not much has changed since the days in which your neighbour flew commercial planes, his “professional radio licence” is basically the equivalent of:
- fill in the form,
- pay the fee, and
- you’re good to push the buttons and talk into the device marked “microphone”.
…and, just for a chuckle, here’s a short video of a pilot “throwing dust in the eyes” of some people - or should that read “throwing some people’s eyes into the dust?” - on the island of St Maarten in the Caribbean. Enjoy!