It's a nice easy tax, airlines have to pay it.
I don't see it resting at this level for long, inflation and the term "Green" will come into play.
APD and Stamp Duty are just low hanging fruit tax that drop into uk.Gov buckets, the buckets have so many holes, they will never ever be full enough to allow the fruit to remain on the tree....
Good Luck, but I think it's fruitless !!!!