This isn’t just aviation licences in isolation. This is being looked at as a huge topic involving the acceptance of professional qualifications across many fields. Accountancy, Law, etc.
This is all part of a huge reset in relations between the UK and the EU. It may or may not happen. But even if it does, it doesn’t mean you can come to the UK and work easily, you would still need the right to come and live and work in the UK, similarly with the EU, or national member state.