Originally Posted by vflyer
Customers who purchased tickets prior to 12 December 2006 will need to pay the extra tax at the UK airport when checking in for their flight. Payment can be made by credit card or cash.
American greatly regrets the inconvenience that this retroactive tax will cause our customers.
American isn't collecting this tax. It's being done inside the borders of the UK itself, by UK citizens authorized and obligated by the UK government to collect the new tax.
American is just informing you of the changed state of affairs.