UPDATE: Apparently news release distribution service PRWeb can't be trusted anymore. I apologize but I have to retract the earlier story that Google had purchased the company. ICOA told the WSJ that the news is false, or, as CNET puts it, "Google got punked."
TechCrunch, The Next Web, GigaOm, also were conned by the fake news.
Here's my earlier report:
Search giant Google announced today that it has acquired ICOA, a Rhode Island company that services broadband wifi Internet networks for airports and other high traffic public spaces, in a deal worth $400 million.
The Rhode Island company provides Internet services to airports, such as terminal-wide, enterprise-class WLAN for airports such as Stewart Airport in Poughkeepsie in New York State, plus back office solutions for hotspot operators in about 40 other US states.
This year ICOA (whose recent financial statement is posted here) announced a capital restructuring plan, with a goal of continuing to reduce the number of shares outstanding by roughly a quarter.
In July ICOA had to unwind a planned acquisition of a majority interest in Tango Software Corporation because of financial difficulty.
Stated Erwin Vahlsing, Jr. CFO:

"It is unfortunate that market conditions at this time have prohibited us from fulfilling our end of the agreement."
Google hasn't stated its purpose for the purchase on its official blog.
UPDATE: 9:52 am. The Next Web points out that,

Tucked away on ICOA’s website is a small page dedicated to advertising. ICOA boasts over 500,000 logins a month from users of its hotspots and offers businesses a chance to advertise on its "portal and landing pages."
Is Google’s advertising business going to add another market to its Adwords product?
Good question. As mobile data demand spikes, can wifi come to 3G rescue of cellular companies who are unable to provide adequate data connections for data-hogging tablets and smartphones?
Just as tantalizingly, Google's ICOA acquisition could theoretically put it in a position to give its wifi business partners the ability to market to Google device owners that access their networks by offering coupons and other promotions sent directly to their phones or tablets.
TechCrunch notes:

Google also announced in September that it would be sponsoring free wifi access at 4,000 Boingo hotspots in the U.S., available to Android mobile devices and notebook PCs.
The sponsorship was linked to the Google Play brand, and was clearly aimed at getting more Android smartphone users doing more with their devices on public Wi-Fi networks.
Wifi has a higher bandwidth than 3G, making such an offer an attractive branding tool. Google's micropayment business model, already linked with user's Google accounts, could make signing onto a Google-owned hotspot easy.
Tnooz notes that the more recent announcement that Google also plans to expand its sponsorship of Boingo wifi from six New York subway stations and more than 200 Manhattan hotzones, to 24 additional locations nationwide.
UDPATE: 10 am
Earlier this year, ICOA partnered with iPhoneTrip.com, America's first international 3G Internet provider, to offer its wifi end users rentals of SIM Cards and iPhones for both local and overseas travel, promising a 3G/GPRS internet connection in 193 countries worldwide.