Originally Posted by
JDiver
It's the Air Passenger Duty, an Excise Tax, that is variable depending on route length...
That's not entirely true. APD is based on the distance from LON to the capital city of the destination (and seat pitch) rather than route length itself. So APD is the same for a LON-BOS ticket (3276 miles) as it is for LON-HNL (7240miles).