Quote:
I have been connecting from elsewhere in Europe, through FRA or LHR on my way back to the US for years now.
Regardless of the combination of carriers used, I will not pay the departure tax from FRA or LHR as long as I am a through passenger (24 hours of layover max) and can prove it.[/b]
Actually it does depend on the combination of carriers used and direction in which you use them. AA can only waive the non-transit taxes (for lack of a better term) if you are connecting from OAL to AA, that's either done automatically, like when you connect via LHR, or through a manual adjustment when you connect via anywhere other than LHR. The non-transit tax is, however, always collected by AA when you buy a ZED ticket that involves an OAL-to-OAL (e.g., BUD-MA-LHR-BA-PHX) or an AA-to-OAL itinerary (DFW-AA-LHR-BA-MOW). The tax is collected EVEN if you intend to make an immediate connection.