Hobbyist wireless LAN sniffers are now taking their war-driving skills to the air, detecting hundreds of WLAN access points during short trips in private planes cruising at altitudes between 1,500 and 2,500 feet. A Perth, Australia-based “war flier” recently managed to pick up e-mails and Internet Relay Chat (IRC) conversations from an altitude of 1,500 feet.
http://www.computerworld.com/mobiletopics/mobile/story/0,10801,73901,00.html