Alaska Airlines this year has been making dramatic changes to Mileage Plan, its loyalty program, as its integration of Virgin America takes shape, and competing airlines make moves on the west coast.

Originally, when the carrier launched a partnership with Finnair in May, rumors circulated that with the merger wrapped up, Alaska may lean closer to a relationship with the Oneworld alliance. American Airlines plays a big role in that alliance and the joint network would seriously compete with Delta, which is trying to expand into Seattle. Alaska already collaborates with Cathay, Japan Airlines, and a handful of other Oneworld carriers.

In July, however, Alaska and American put the brakes on their relationship when they announced that frequent flyers on either side would soon only earn points on codeshare flights rather than network-wide. Relations between Delta and Alaska, meanwhile, continue to sour as the two carriers take turns at launching promotions to steal each other's best customers.

Now, Alaska and Singapore Airlines are teaming up to offer loyalty program perks and a codeshare agreement. Announced late last month, the relationship will allow Singapore Airlines to codeshare domestic flights on Alaska Airlines, effectively expanding its international network from Singapore into Alaska's west coast hubs, and then deeper into the United States.

Starting on September 27, Mileage Plan and Krisflyer members will also be able to earn frequent flyer miles and book award flights on the opposing carrier.

Curiously, Singapore Airlines is a member of the Star Alliance, a network to which United Airlines subscribes. Among Alaska's myriad alliance partners, the majority are in the Oneworld alliance, though several, like Fiji Airways and Emirates, operate independently like Alaska. Outside of Singapore, Alaska has no other partner carriers in the Star Alliance.

Looking at Alaska's strategy out of Seattle and the west coast at large, though, the decision to work with Singapore makes more sense. Alaska already partners with a handful of international carriers such as Cathay Pacific, Korean and Japan Airlines that connect through the west coast. By working with these international players, Alaska can let its customers reap the benefits of a long-haul network without actually operating it.

This sort of utility, as well as the program's distanced-based earning program, may be what makes Mileage Plan members like it so much. Already, the program has racked up several awards as the best airline loyalty program this year. If it continues to grow in reach and flexibility, its ranks could swell.