I like fresh ideas to reduce flights. This seems onerous to implement.

You need a central EU database on who is flying where and in which class.

In their paper they mention that the carrier needs your tax status to calculate the full fare. This will enable all kinds of shenanigans for quoting you a different price because they can estimate how price-sensitive you are.

It would be fun for HR departments. By the time I make my first non-business flight, half a year is already over and this a couple flights for the job. Who pays the tax for that?

https://stay-grounded.org/wp-content/uploads/2022/04/Frequen...

>> The levy would start at zero for the first return flight in 12 months and rise by €100 for each return trip, with surcharges for longer distances and first class travel.