If you're planning on flying this holiday season, make sure you pack your laptop.

Google is offering free WiFi service in 47 United States airports, including Milwaukee's Mitchell International. In addition to Milwaukee, travelers using Madison Regional and Central Wisconsin Airport in Mosinee will also get free access.

Google, however, is asking travelers to "pay it forward." The company is asking the WiFi users to utilize the "Google Checkout" program to make a donation one of three charities. The company will match donations up to $250,000.

The free WiFi service is available now until Jan. 15, 2010.