American AAdvantage has a great bonus offer for transatlantic flights on American, British Airways, Iberia, or Finnair. Registration required.

This is for travel between September 9 and December 9 — but it’s only offered if you bought your tickets September 9 or later.

The idea here is that the promotion is generous, they don’t want to give extra miles to people who were already planning to travel — only people that might have been motivated to travel or to pick one of American’s joint venture partners to travel on by this bonus.

Still, it also says ‘we take our most loyal customers for granted’ if you’d fly us because you’re loyal we don’t value that. I’ve long said I hate bonuses excluding pre-existing bookings.

Here’s the bonus:

The nice thing at least is that this isn’t just a bonus for premium cabin fares, even the bulk of discount economy fares will earn something (for American flights this includes H, K, M, L, W, V, G, Q, N, O and S fares). And also that one-ways earn, too (at half the amount listed in the chart).

You’re not likely to fly to Europe just for this offer, but it can make great deals – especially any premium cabin sales on British Airways (stacked with a $400 AARP discount and 10% co-brand credit card discount) – that much better. And it’s worth registering to have gotten that taken care of, so you don’t need to remember later.

American Airlines Business Class

(HT: JT Genter)