I recently sat next to an Alaska VP on a flight and he said a lot of the PDX up-gauging on late night/early morning flights from Seattle has to do with lack of space to park aircraft overnight in SEA and taking advantage of the demise of the Q400s to move the same amount of pax on fewer planes. I’d add to that given Alaska has taken away so many PDX nonstops that you pretty much have to go via SEA to get anywhere and that adds more people needing to fly the route. I’ve done SEA/PDX five times in the last four weeks returning late from trans/mid cons and there is a real flurry of activity and late arrivals into SEA moving pax from different PDX flights. It’s nice to know if I arrive into SEA early or late I stand a better chance of finding an empty seat on a 900 vs a Q400 even though it takes much longer to board the plane than fly the route.