Yesterday I saw American’s American’s progressively bigger bonus on European flights, saw that only higher fares qualified, and didn’t get especially excited.

This morning I realized that it was worth paying more attention to — because some of the fares that qualify for the bonus aren’t actually that expensive, that many folks will find themselves flying on qualifying fares anyway, and that the increment to ‘buy up’ to a qualifying fare is in some cases not that much and potentially worthwhile to earn the bonus. So it made sense to post about this.

Here’s the offer:

The More You Fly. The More You Earn. Fly round trip between the U.S. or Canada and Europe on First Class, Business Class or select Economy Class fares* and start accumulating American Airlines AAdvantage® bonus miles. You will earn the bonus miles whether you fly on American Airlines, British Airways or Iberia.

You’ll earn 15,000 bonus miles on your first roundtrip, 35,000 on your second, and 50,000 on your 3rd and each successive qualifying roundtrip between September 25 and January 31.

Registration is required with promotion code AAEUR.

This promotion is open to US and Canadian residents. (European residents should see this similar bonus.)

The following fares qualify:

Includes First Class and Business Class fares booked in F, A, J, R, D or I; Economy Class fares booked in Y, B or H on American Airlines operated flights; First Class or Club World fares booked in F, A, J, R, C, D or I; World Traveller Plus or full-fare World Traveller booked in W, E, T, Y, B or H on British Airways operated flights; Business Class fares booked in J, C, D, R or I; Economy Class fares booked in Y on Iberia operated flights.

The keys here, to me, are that World Traveller Plus fares on British Airways count. These are a reasonable deal, and especially because BA’s premium economy tickets are one of the few exceptions to my rule that award tickets are a better use of miles than upgrades. (With American miles you have to have booked full fare premium economy to upgrade, and the tickets must have been booked through American. But with British Airways Avios the lower premium economy fares qualify. Upgrades to business come out of the same inventory as award tickets.)

And also that “H” fares are often about what you’ll pay anyway to go to Europe, or not much more.

For instance in November New York – London is coming up at about $750 for the cheapest fares, while H fares are about $1420. I’m not sure it’s worth doing three of those at the higher price, an extra $2000 to earn 100,000 bonus miles is about a break-even proposition. If you’re doing fewer than three trips that wouldn’t be worth it at all, more than three trips (earning an incremental 50,000 bonus points for an extra $670) does seem worthwhile to buy up.

And the example assumes you’d be getting sub-$750 fares as the cheapest possible. Whereas many will be paying more, and higher fares involve fewer miles and lower co-pays to upgrade.

While I often dismiss outright bonus promotions requiring high fares, there’s at least the possibility that it’ll make sense with this one, for some readers.