The airport authority-controlled Wi-Fi networks at several airports are shaping up as ground zero in an emerging battle between airlines and airports over the use, regulation and management of wireless networks at the facilities.

A wireless network at Logan International Airport in Boston, a similar system at Denver International Airport (DIA) and others planned for the Raleigh-Durham International and Los Angeles International airports are at the center of a fight over the unlicensed wireless spectrum used to support a wide range of applications, from passenger Internet access to remote check-in kiosks.

When Logan turns on an airportwide Wi-Fi network next week, airlines and their passengers will have to pay to use the network, something United Airlines Inc. views as an "unnecessary expense," according to Mike Mader, a ground systems radio engineer who handles Wi-Fi installations for United.

While passengers can choose whether or not to pay for access to Wi-Fi hot spots at Logan, airlines, which use Wi-Fi networks to support key applications such as bag tracking, have no choice, according to Barbara Platt, a spokeswoman for the Massachusetts Port Authority. Massport, which operates Logan, requires airlines and other airport tenants to use the Universal Wireless Ethernet System (UWES) installed at the airport, Platt said.

United, a division of UAL has installed its own Wi-Fi networks to support bag-scanning operations at numerous airports, including its Chicago hub. But Mader said the carrier will have to use the Massport network under the mandate imposed on all airport tenants. That's not as cost-effective as United installing and operating its own network, Mader said.

Platt said the UWES provides for better management of the wireless spectrum at the airport and "ensures Wi-Fi runs smoothly for all users." Platt declined to provide pricing details.

TWI Interactive, developed the Logan network in partnership with Electronic Media Systems. TWI said its five-year contract guarantees Massport a minimum payment of US$200,000 in the first year of the pact and as much as US$300,000 in the fifth, up to a maximum of 20 percent of gross revenue. That revenue could exceed US$1 million annually.

Chuck Cannon, a spokesman for DIA, said payments from its Wi-Fi contractor, AT&T Wireless Services, could run about US$250,000 per month. Like Massport, DIA maintains that it needs to manage the Wi-Fi spectrum in the unlicensed 2.4- and 5-GHz bands to ensure frequency and spectrum coordination, according to Jim Winston, director for telecommunications at the airport. DIA is owned and operated by the city of Denver.

"If we don't coordinate, it's going to be a zoo out there," Winston said. If the airport let all its tenants install Wi-Fi networks, "there would be mass confusion," he said.

Jeremy Denton, director of government affairs for the Industrial Telecommunications Association (ITA) said that from his perspective, revenue -- not frequency coordination -- stands behind the move by airport authorities to control Wi-Fi networks. The ITA is a trade group that counts among its members airport Wi-Fi users such as United, FedEx and United Parcel Service.

In a filing with the Federal Communications Commission in March, the ITA said that the "sole motivational goal" by airports to regulate Wi-Fi use "is to increase the airport authority's revenue." The ITA has asked the FCC to issue a declaratory ruling against airports' attempts to regulate the unlicensed spectrum, saying they have no legal standing to do so under FCC rules.

While Denton would like to see the FCC rule quickly, he predicted that the agency would put the ITA filing out for public comment, a process that could take a year or more. Massport's Platt and DIA's Cannon both declined to comment on the filing.

Based on his experience at DIA, Mader said not only do airport-controlled Wi-Fi systems impose extra costs, they don't immediately deliver what's promised. Mader said he has worked since October to resolve coverage and interference issues with the AT&T Wireless network at DIA because the access points installed for the Wi-Fi network used by United for its bag-scanning system don't provide the needed coverage.

United wanted the access points to cover the ramp area out to and beyond the tail of a Boeing 777 to support scanning of late bags loaded into the plane, but the signal didn't reach that far. Mader said United also experienced interference from another 2.4-GHz network, which was traced to the DIA central car-rental facility, close to a mile from United's gates. All these coverage and interference problems have now been resolved, but it took about six months longer than the time it would have taken United to do the job on its own, Mader said.

Winston blamed United for the problems, saying the airline was unable to figure out coverage issues on its own. "They don't have the expertise," he said.

John Killeen, global network systems manager at UPS, said the company operates Wi-Fi networks to sort packages at about 90 airports. Airport attempts to control Wi-Fi spectrum are a minor issue today, but if the FCC ruled in favor of airports as a result of the ITA petition, airport control could become a "potential problem." Killeen said he would like to see the FCC act quickly on the ITA petition.

Ken Pasley, director of wireless business development at FedEx, which also uses Wi-Fi systems to sort packages, said airport attempts to control spectrum "could clearly affect us," though probably not as much as passenger carriers, since FedEx operations are far from terminals where shared-use networks have been installed.

Pasley said he supports the ITA petition and views airport-owned and managed Wi-Fi networks as a way for them to boost revenue.