Delta has a better product than Alaska, a worldwide network, great management, and motivated employees. On a level playing field Delta would crush Alaska. The limiting factor, and Alaska's shield, is the lack of gates at Seattle. The same real-estate constraints are also what protect Alaska from ULCCs in Seattle. There's such a huge travel demand in Seattle that whoever owns those gates will make a profit. Alaska was lucky in that it arrived first and there's now not enough room for anyone else. With One World, and the American code share, Alaska can remain the poor man's Delta alternative as long as the city doesn't build another terminal.

Outside of Delta in Seattle, there's also a future risk to Alaska Airline's other revenue honeypot: the state of Alaska. As America moves away from an oil economy over the next couple of decades, demand for flying inside Alaska will dry up as well as the subsidies that support many of the smaller communities that Alaska Airlines serves up there. Unless someone figures out how to turn Alaska into the next Iceland and drive some millennial tourism up that way, I don't see much new revenue potential up there past 2030.