LAXLHR
That's a very good post.
I cannot believe that a Conservative chancellor is even contemplating subsidizing one private business over another. Total market distorting economics of the mad house.
Also I wonder: 'IS THIS EVEN LEGAL?'
One of the scenarios you point out might lead to a test case in the EU Court.
Then we'll all end up wasting even more public money on expensive lawyers.
The best way to create extra business in all regional airports AND create a level playing field is to reduce or eliminate APD for non London airports.
London is different because demand outstrips supply - taxation policy can therefore be an effective tool for constraining demand whilst supply issues are being resolved.
For everywhere else it just crushes growth potential.