"Microsoft Dynamics 365, as that's really all the database is, a customer tracking system."
Based on my experience, using Microsoft Dynamics will likely cause this requirement to cost both £4m and £100k.
The Dynamics version will take consultants 3 years to produce something that doesn't work before the CAA give up and then spend £100k to implement a basic customer tracking application that's supported in-house. The in-house application may be a spreadsheet.
Drone users will still be charged £16/drone and no one will end up happy. But at least something works right?