http://bits.blogs.nytimes.com/2011/08/05/a-homemade-drone-snoops-on-wireless-networks/?hpw

It’s a remote-controlled plane with a computer in its belly that
can fly up to 400 feet above the ground, snoop quietly on wireless networks
below and attack one if it wants to. It can also pretend to be a GSM cellphone
tower, eavesdropping on calls and text messages that pass through.