An article I wrote for the Royal Aeronautical Society on some of the under-reported operating costs.
Links here:
https://evtolinsights.com/2023/05/feature-how-much-does-it-really-cost-to-run-an-air-taxi/
or
https://www.aerosociety.com/news/in-the-latest-issue-of-aerospace-may-2023/