In September, I complained about the uniformity and lack of selection in airport bookstores. I am happy to report that Portland International Airport (PDX) stands out as an exception, having branches of Powell's Books either side of security. The one outside security was staffed when we arrived about 8 pm; the one inside security on Concourse C was staffed when we were waiting to board our return flight about 7:15 am.
Should have I bought books on each passage to encourage the business? Perhaps, but on the way in, I expected to have a chance to visit the main store downtown; on the way back, I had with me the books from that visit.