Atlanta’s Hartsfield-Jackson, claimed to be the busiest airport in the world (and maybe still is, but several in China are catching up fast) will soon offer free WiFi throughout all terminals. The plan has been in the works for several years but has been delayed; the City Council is expected to approve it next week.
When completed, the system will support 15,000 connections, nearly 4 times as many as can connect to the current paid system. Details from Atlanta Journal-Constitution.