At the Portland airport today traveling after an excellent Portland DrupalCamp. The day got busy yesterday and I fell behind in updating my post but that will come later. In the meantime it is worth sharing how an airport does Wifi the correct way.
So the first thing is that WiFi, yes even in airports, should be free. This is not a service to offer only to those who will pay for it. It is a way of making sure people like your airport and your city so they will come back again. Boise, Portland, Las Vegas and others get this. Unfortunately San Francisco and Denver are amongst the airports that don't realize this.
Some airport WiFi seems to work marginally. Portland on the other hand has a very solid service at PDX. In addition when you sign in instead of a generic page you get a very useful map showing what part of the airport you are located in and where other access points are.