American Airlines' long-haul fleet leans heavily on the Boeing 787 Dreamliner — 70 of them, with 19 more 787-9s on order — and its 'Flagship Business' cabin is the premium product you'll find at the front. But what you'll pay for one of those seats varies wildly depending on where you're flying and when.

Transatlantic one-way fares swing from around $2,200 to over $11,000, and tickets originating in the US typically cost more than the same seat booked from Europe. The Dreamliner does most of its Europe work out of Philadelphia and Chicago-O'Hare: the smaller 787-8 covers cities like Athens, Dublin, Amsterdam, Barcelona, Prague and Nice, while the larger 787-9 flies the heavier routes — London-Heathrow, Paris, Rome, Lisbon and Edinburgh. You'll also find 787s to Europe from New York-JFK, Miami (Milan only), Los Angeles (Heathrow) and Dallas/Fort Worth (Frankfurt and Heathrow).

Asia is where the value gets interesting. Fares run roughly $3,100 to $8,500 one-way — cheaper than Europe despite the longer distances, a sign of American's weaker competitive position against Delta and United there. All 787 flights to Asia use the 787-9: New York to Delhi and Tokyo Haneda, Dallas to Tokyo and Shanghai, and Los Angeles to Tokyo. Meanwhile, South America is American's stronghold via Miami, with one-way business fares between about $2,300 and $5,400 — the cheapest of the three regions. The 787 serves Buenos Aires, São Paulo, Rio de Janeiro and (seasonally) Santiago.

If you'd rather pay in miles, be warned: American prices awards dynamically, so those advertised starting points — 75,000 miles to Europe, 90,000 to South America, 95,000 to Asia and the South Pacific — are best-case figures, not typical ones. AAdvantage miles work on all oneworld partners plus a handful of others like Etihad and Qatar Airways, and Citi cards transfer one-to-one. Hotel transfers are poor value: Marriott Bonvoy at 3:1 and World of Hyatt at 5:2.

The seat itself depends on which plane you get. Older 787-8s (20 of them) have the Safran Concept D, a paired-seat design criticised for transferring movement between neighbours. Later 787-8s and the first 22 787-9s carry the Collins Super Diamond, a reverse-herringbone seat similar to what American puts on its 777-300ERs. The newest '789P' 787-9s — premium-heavy at just 244 seats with 51 business suites — feature the Elevate Ascent with privacy doors, plus front-row 'Flagship Preferred' suites with extra space that, for now, carry no surcharge. That's likely to change.

For travellers, the practical takeaway: Philadelphia and Chicago are your best bets for 787 business class to Europe, South America offers the best fares per mile flown, and if you can snag a new 789P aircraft on a Tokyo or Delhi route, you'll be flying American's best business seat. Book US-originating tickets carefully — the same trip starting in Europe can cost far less.