Atlanta's Hartsfield-Jackson airport (ATL) would like to offer its passengers free Wi-Fi: Economic conditions don't allow that switchover, however. The Atlanta Journal-Constitution says the airport sees 25,000 to 40,000 connections each month, which brings in $1m. If that were the airport's share, that's $2-$3 per connection, which seems rather high since many travelers are using roaming systems based on other numbers I've seen. Some percentage is paying $8 for a daypass, sure, but that shouldn't be half.
ATL renewed contracts until 1-August-2011 with three providers, which include Boingo and T-Mobile based on the network's splash page. A hybrid system is under consideration, where service would be free to casual users, but corporate users would have access to for-fee networks to which they had plan access. The free network would display ads.
Atlanta is the busiest airport in the world, and would be only the second very-large airport, following Denver, that opened its network for ad-supported, free use. Most other free airport networks are in second- and third-tier markets that carry plenty of passengers, but use free Wi-Fi as an amenity to attract travelers away from first-tier hubs.