I've heard similar about the demographics of BLI passengers, although the weakening Canadian dollar has reportedly pushed the Canadian share of the passengers down to a little over 50%.

The population comparison isn't quite the full story because those 700,000 Vancouver area residents have a choice between BLI or Vancouver. The main motivation, I'm told, is price, but for probably around 1/2 of them, BLI is closer than YVR if there's no border wait.

I'd say Alaska's characterization that there's roughly 1 million people in the area where a similar travel time advantage exists for PAE versus SEA is probably about right.