That was my exciting (spoiler! It was not exciting) Friday evening: riding a bus then the MAX to Portland International Airport, watching planes launch and land, reading and enjoying the fantasy western Silver on the Road by Laura Anne Gilman (suricattus), and just watching the bustle of humanity as it came and went. PDX is a user-friendly, visitor-friendly airport, and even though I haven't flown in or out of there since 2010, I like knowing it's there.
I've been airport-visiting as long as I've been able to drive. I used to drive to Washington Dulles International Airport when I lived in Northern Virginia, just to hang out in that terminal. And also go out on the observation deck, pre-9/11 when you could do that. Dulles still doesn't have rail access (that's coming, though), but Washington National does, so sometimes back then I'd ride the subway to that airport too. (And no, I don't want to call it Reagan National.) I now find it a little weird if I don't go to an airport near where I live; I never went to the Eugene airport during my four years living there, for instance.
My TriMet pass continues to be used well.