Is that politicians cannot leave well alone and keep them as Pigou Taxes.
Air Passenger Duty is a good tax, in that it does indeed correct for the externality of the emissions from planes. That rate has been pushed too high of course, because that’s what people who get to levy taxes do with them. And this problem is encapsulated here:
“However, it is important that the aviation sector plays a part in helping to bring down the deficit.”
No, a Pigou Tax is not there to raise revenue. It’s a nice side effect but that’s all. The rate must be at the cost of the externality.
And that of course is what is wrong with Pigou Taxes. That they’re open to being misused in this manner.
Still better than regulation or banning of course, but not perfect for the usual political reasons.