I'm not sure about the specific airports on your itin, but a very small number of airports have free wi-fi available, many have pay wi-fi. There are a variety of providers, so pricing plans vary. Most offer a full day plan for $7-10, some offer time in more granular increments, starting at around $3.00. Just plug the card in, if you get signal, open a browser and go to any address. The provider will hijaak the browser to a page that describes your options.