Access at airports can vary. It seems to me that in the US they want to charge you but many airports offer ways to connect if you are already a customer of A&T, T-mobile or some other similar service. When out of the US I’ve found free access, at least it was when I was in Costa Rica and Egypt (both in the last 18 months).
Give me free Internet access at the airport and I’ll be early for my flight! I just hate being too early and having nothing productive to do.
Some of the airport privileged frequent flyers may get free access so if you can find a location near one of those areas you might me able to get leech some access from there for free. I’ve seen this in some hotels too, if there is free access in area, it leaks out to the other areas too.
I know from recent experience Detroit and Atlanta do require a charge (or membership with one of the WiFi companies) for the Internet, but one of the Las Vegas airports (McCarran Airport, Las Vegas, Nevada, USA) do not. But remember, airports are big and access may vary depending on where you are (McCarran only has it in certain terminals). And finding power isn’t always very easy…