Alaska Airlines is a pseudo full service airline and has its largest operations at  Seattle Tacoma Intl Airport, United States. Alaska offers complementary food and beverage service to its first class customers, with buy-on-board available to all other passengers. It operates an exclusively short-haul narrowbody fleet composed entirely of B737 variants, with an average fleet age of roughly 10 years. Alaska's frequent flier program is Mileage Plan, and it is not a member of any current Alliance. It does, however operate  extensive code-share flights with airlines such as American Airlines, British Airways, LAN Airlines, Korean Air, Air France and Delta.