Call it a holiday gift from your friendly mega search engines. First Microsoft teamed up with airport and hotel mobile-ad network JiWire, offering free public WiFi access in exchange for one search on Bing. Yahoo followed by rolling out a free hotspot in New York City's Times Square.

Then Google announced Tuesday it would give away free access through the holidays at 47 airports through Jan. 15, including Las Vegas, San Jose, Boston, Baltimore, and more. Airports in Burbank, Calif. and Seattle, Wash. will begin offering airport-wide free WiFi indefinitely.

As a way to give back, Google asks consumers to donate to one of a few charities when signing into WiFi service at participating airports.

Consumers can choose to make a donation to Engineers Without Borders, the One Economy Corp. or the Climate Savers Computing Initiative. Google will match donations up to $250,000. The airport network that generates the highest number of donation dollars per passenger by Jan. 1 receives $15,000 to donate to the local nonprofit of its choice.

If you're flying home for the holidays, it seems WiFi public connectivity on airline flights keep dropping in price, too. In May, Virgin America began offering Internet service from its provider Gogo Inflight on every flight. Typically, passengers would pay between $5.96 and $12.95, depending on the length of their flights. For the holidays, though, any traveler on a Virgin America flight will get free WiFi access from Google and Gogo.

  While the search engines' generosity gives consumers free public WiFi service, and charities a little more in their coffers, the gift from Google, Yahoo and Microsoft could also give advertisers holiday cheer by turning up the volume of searches, clicks and, possibly, conversions on pay-per-click or display ads.