I have been flying to/from Seattle on international routes (mostly to Europe) for several years and on several airlines. I thought I'd summarize the experience here. It may be useful to other Seattle-based travelers. Airlines to/from Europe: IMHO British airways offers the best accommodation on board, international lounge in Seattle and plenty of connections once at LHR. They partner with Alaska, so it is relatively convenient to use Alaska domestically and BA internationally, consolidating miles on Alaska. EQMs do not accrue in that case, only redeemable miles. Economy seats are uncomfortable anyway, but at least BA offers a "proper" premium economy cabin with wider seats, better legroom. In business class they have lie-flat seats in pods that allow a modicum of privacy. I never flew first class with them, so I cannot comment. Delta flies to AMS, CDG, soon to LHR and plenty of domestic destinations. It also partners with Alaska. In terms of convenience, it is difficult to beat it. Alas, the economy seats are quite uncomfortable for long trips for anybody but a child, pretty much the same you'll find on a domestic flight. Premium economy is a joke - same seats with about 3" more legroom. Business class seats do not fold flat, although I am told that the planes will soon be fitted with more modern ones. The lounge is bright and spacious, but other than that it is pretty much the same as a domestic one. Food selection is poor, cleanliness is spotty. A common problem seem to be the restrooms: too few and rather unpleasant. Those in the main concourse are often cleaner. Lufthansa flies to Frankfurt, which afford many connections on star alliance worldwide. They partner with united, which has comparatively few flights out of Seattle. Their economy class seems a bit more comfortable than others', perhaps the seats are more generously padded. I could not find other differences. I understand that they will soon introduce slimline seats. If they are at all similar to United's new ones, they will be quite uncomfortable on a 9.5 hr flight. They have no premium economy (again, that's supposed to change in 2014). Their business seats do not lie flat either and I found them less comfortable than Delta's - they lie at an awkward angle for my back. Their lounge is nothing to be proud of. It shares the same issues as Delta's without being spacious. Food on board is comparable and often a matter of preferences. In economy, Lufthansa was the worst, ba and delta tie (it does not mean they're any good, though). In business, on the other hand, I found the opposite was true. Lufthansa served quite a tasty meal. As for points redemption, Lufthansa/united used to be the winning combination. However, availability seems to have worsened in most classes over the last 6 months or so. United devaluation does not help either. Economy stayed the same, business increased a bit. BA used to have decent off-peak availability, but the summer or any other holiday period has always been difficult, even 6+ months in advance. As of now, there seems to be nothing for next summer to and from Seattle. Vancouver has so far been better in that respect, if you do not mind the drive. On top of that, they charge fuel surcharges and taxes to the tune of $600+ for an economy reward ticket. Note that it is the same amount for premium economy, but significantly more for business. Delta will be Delta: availability of saver awards is severely limited on all routes. Plan to book 9+ months in advance. As for points collection, the ranking inverts. It is easy to accumulate on Alaska by flying delta, Alaska, ba, American and emirates. It is rather difficult to spend those points for flights to Europe, though. You'll have many destinations but restricted availability on each route. United/Lufthansa are more difficult to accumulate because of the relatively few direct flights. Delta miles are a non starter for me. Alaska offers more flexibility from here. I wish that either Amex or Chase added Alaska to their respective points programs. Alas, that is not the case so choices are limited: Chase UR will let you transfer to united and BA Amex Mr will let you transfer to Delta and BA Bank of America has an Alaska Visa card, but its accumulation rate is only 1 mile per dollar spent - no category bonus except on Alaska tickets. As I will spend most of my accumulated miles this year, I plan to start afresh next year. So far collecting on Alaska to spend on Delta or BA seems the best bet to me. The credit card may not be the best, but there will be more routes to choose from and United/Lufthansa availability has gotten worse anyway. What do you think?