The UK has a departure tax (‘Airline Passenger Duty’) that’s high in coach and higher still in premium cabins, and is often referred to as a ‘premium cabin departure tax’ or ‘luxury tax’.
One improvement, implemented a little over a year and a half ago, is that children under 12 flying economy no longer pay this tax. On a London – New York ticket that’s a savings of $96 per child, which really adds up for a family traveling with several kids. However American Airlines is still collecting the tax on award tickets.